This book is well worth grabbing if you are at all considering self-publishing your book (not to be confused with subsidy press publishing):
Books: Tips, Stories, & Advice on Writing, Publishing, & Promoting by Dan Poynter
Dan Poynter is a bit of a legend when it comes to self-publishing and marketing books, and helping others to do the same. This may also deal with traditional publishing and the art of writing marketable material; however, I haven't read it, so I'm just going on his other books.
This book was made available for free on July 9. It won't stay free for long, so don't delay.