Came across this very nicely done site: Convertup.com. The founder of this site (make sure to subscribe to his ConvertUp web usability blog -- the articles are great) has numerous tips about web usability testing. ConvertUp publishes articles and offers services to help people increase their site’s conversion rate by offering a usability testing service. The premise of this site is that, in general, by making your site more user-friendly you will be able to convert your existing site traffic into more sales. (Get it? "Convert Up").
I liked what the author said about this himself:
I consider myself an “Internet Marketing Coach”. I am passionate about helping people create successful online businesses. Whether it be usability (my specialty), search engine rankings, or general website marketing strategy, internet marketing is on my mind all day, every day. When I find precious few hours to sleep, I dream about internet marketing. I realize the internet is a big place, but I have this silly notion that I can make it better and more user-centric by sharing my usability knowledge through my service and my blog. Source
Well, I don't always dream about internet marketing in my sleep, but I like to read articles by someone who does!