It's a good idea also for the text to read what your main keyword is. For instance
www.a1cleaning.com can be seen as "Carpet cleaning in Houston". Maybe Mark can verify but I think it earns a few points with the engines. Getting into local directories is also good specially if they are related like a page dedicated to "Cleaning services in Houston". I see you're linking to a couple of good ones John. What else did you do to get a page rank of 3, that's awesome.
Tom, search engines don't like it when code is buried. If the algorithm catches on your site may be banned and may be real hard to get back in good ranks.
BTW, there's a couple of guys in the ICS board that are experts at this. One is Darrell (forgot last part of his handle) that moderates a search engine board. Maybe he can come in here and talk about it.
Albert