Andy's doing a nice series on promoting your software. The first one is here:

http://successfulsoftware.net/2007/05/07/promoting-your-software-part-1/

Every time I read this type of series I always think the author is finally going to give me the super secret idea for selling millions of copies. Surprisingly I always end up disappointed. Never the less it's a good read if you're starting out in the biz.