Another good book is The Computer Consultant's Guide - second edition - Real-Life Strategies for Building a Successful Consulting Career by Janet Ruhl. Originally written in the early 90s, it was updated in 1997 to the 2nd edition with updated information. Though it still shows its age a bit when talking about technical matter, I consider the advice and information contained in it to be invaluable. It has lots of great information about setting rates, contracts, etc..