Search Engine Optimization:
"SEO" or search engine optimization by a company that "specializes" in it is not something I usually recommend to our clients as simple and low-cost methods such as those mentioned here can be an effective marketing plan.
If you do consider a specialized company for this type of marketing I recommend you get a number of different quotes and exact details and costs of what services will be preformed. I do not recommend anyone re-write your website text for the sole purpose of loading it with key words and phrases. I do recommend you have a professional copywriter evaluate your text so that it is as effective as it possibly can be for your market and that key words and phrases are utilized in areas such as headline, page titles, images tags and your description tag (in your page code).
Google is still the top dog as far as engines go and Yahoo is the top directory site, so a simple focus on keyword campaigns is often much better use of your online advertising budget than paying a SEO company. Google's main qualifiers for ranking include: quality links (links to your site from other quality, well-ranked sites), quality content (it's important that your text is well-written for a human, not a robot), quality page coding (make sure each page has a title tag which can include your key words or phrases, every image has an "alt" tag which can also have descriptive keywords/phrases, and every page has a description tag - again with description words/phrases - your web designer/developer should be able to do this). Here is another good link to read to learn how the "Googlebot" works: http://www.google.com/support/webmasters/
Marketing is Not a One-Time Effort: The last thing to remember is that marketing isn't something you do once and forget about. It requires on-going effort and maintenance. You should be continually evaluating what works and what doesn't while exploring even more new avenues. A few additional web resources you can check out to stay on top of your marketing efforts are:
http://www.jvmediadesign.com/blog/ http://www.wilsonweb.com http://www.marketingpower.com

Sitemaps:
Have you made a Google Site Map for your site? You can check out Google's Webmaster tools at https://www.google.com/webmasters/tools/docs/en/about.html or you can also use a free automated online sitemap generator such as: http://www.xml-sitemaps.com/ (and this site explains a lot more about the sitemaps http://www.auditmypc.com/free-sitemap-generator.asp). Then upload the file to your site, login to Google and submit the link to it. You can also do the same thing for Yahoo. These files help the crawler robots that visit your website by alerting them to all the pages on your site, the frequency that you update your site and other important information.
Banner Advertising:
I have found over time that banner advertising isn't as big of a bang for you buck for a small company as something like Google AdWords. The two positives of banner ads are that they may build brand recognition for you over time (people constantly seeing your company name/logo) and they can help direct potential customers right to a specific page on your site. The drawbacks are that a very small percentage of people actually click on the ads and they are usually costly (you can read a more in-depth article about that here: http://www.thomasclaburn.com/2002/06/the_banner_ad_is_dead_ok_not_r.html). If you do consider banner advertising, make sure the site you're advertising on gives you a way to view statistical information about clicks from your banner and find out whether they charge per-click (and if they do, if they have any contingencies for click fraud), per month, or in some other manner.

AdWords and More:
Setting up an AdWords campaign is the quickest way to get a listing in Google, so if you've taken that step, you're on the right track. It's important to continually evaluate how your key phrases are doing by analyzing the data in your AdWords account. For smaller campaigns it's recommended to check this at least once a month and for larger ones, weekly to daily. This way you can determine which phrases are performing better than others so you can make the most out of your advertising dollars. It's also a good idea to use Google's Analytics program (placing small amounts of code on the website pages that you are directing visitors to in your advertisements). Yahoo also has paid advertising you can check out: http://searchmarketing.yahoo.com/as . Since Yahoo is a directory and not a search engine, they also have directory listings you can purchase to target your market worldwide, or just in your local area.

Blogs:
You've got your blog set up on your website but have you also submitted your blog to blog directory sites? Do you post regularly? Do you "ping" your blog every time you post? A previous article I wrote explains both submitting and pinging more thoroughly: http://ezinearticles.com/?So-You-Have-a-Blog,-Now-What-Do-You-Do-With-It?-Blog-Basics&id=49187
I must reiterate setting up your blog on your own website. Services like Blogger or Blogspot are nice and easy to use, but you get the most effective marketing use from a blog if it resides on your own website. Here's why: all the pages you add to your blog add to the content of your website. It also keeps your content fresh and up to date and increases the overall number of pages on your site, making it appear more favorable to engines like Google.
Also, you can double your marketing by submitting articles you write for your own blog with other sources such as http://www.ezinearticles.com and http://www.goarticles.com. It's free to sign up as an author and post articles. It's important at the bottom of your article to include a link back to your website (or page on your website that you would want people to land on). This gives you inbound links when others use your content on their website, another important factor the top search engines and directors take into account.
Press Releases:
If you're not a writer, consider having a professional review your release before sending it out. Spelling and grammatical errors are a big no-no and a professional can rewrite or advise you on how to effectively promote your company, product, or service with a well-written release.
Don't forget that there are now many online resources where you can submit your press releases. Prices range from free to $50+, depending on the additional services some sites offer with submission. One of my own favorites is http://www.webwire.com.

Website Advertising & Questions to Ask Yourself After Your Launch by Sherry Holub

You've done your homework, researched your target market, researched your competitors, got a professionally designed website and just started promoting it. You've submitted your URL to Google (http://www.google.com/addurl/, set up an AdWords Campaign (http://www.google.com/intl/en/ads/), installed a blog, submitted your URL to relevant free directories, sent out a press release to newspaper and print magazines, and made sure to print your URL on all your business cards, letterhead, etc. So now you just sit back and wait for the business to start rolling in, right?
Not exactly...
Online advertising for your website is an on-going process that should be reviewed on a month-to-month basis. Don't rely just on one avenue of promotion to skyrocket your site up the search engine rankings or dramatically increase your sales. A diversified plan monitored on a regular basis is your best bet for long-term success.

Home Business Classified Ads That Sell Like Hot Cakes by Carael Knight

Different advertisements and even home business ads can have remarkably different results. It depends a lot on what they say and how they say it. Little wonder that many businesses have always preferred to hire ad experts to run their campaigns for them and to design and carefully word their ads.
Still there are some basics skills that anybody can learn about how to construct an advertisement for maximum impact.

After you have written your classified ad, you will need to ask yourself what nagging problem it addresses or what "headache" it offers a cure for. If your classified ad fails this basic initial test, then chances are that it will not be effective in getting you a good response or selling your product. Always remember that readers are selfish and will constantly be asking themselves the question; what is in it for me? Your home business classified ad needs to answer that question effectively and conclusively to be really successfully.

Another very important point to remember is that classified ads work best when they are used simply to establish contact or generate leads rather than to directly sell. The whole idea should be for you to gather a large amount of names which you can then use to creatively communicate your offers and the strengths of your product. The idea here is that very few people will buy from a business that they are not familiar with so the frequent contact after getting a name from a data base is very important to help you sell your home business product like hot cakes.