I just found a cool, free tool you may be interested in if you find yourself stumped for keywords. The Keyword Suggestion Tool is a utility that shows results from Wordtracker and Overture and determines which words and phrases are searched most often.
Often when you submit your blog or website to directories, you are asked to enter keywords that you think people will search on. This tool can help you come up with relevant keywords.
P.S. I learned about this nifty tool on a post on Paul Chaney’s Radiant Marketing Blog. Gotta give credit where credit is due.