I'll admit that I am a sucker for productivity/personal development books and have a house full of them. Some of them are good, some of them are bad, and most have them have the odd nugget of useful information in them.
I have just finished reading Career Renegade: How to Make a Great Living Doing What You Love by Jonathan Fields and it was one of the best I have read. It was full of useful, practical advice for people leaving corporate life and going out on their own. From how to work out what you really want to do to very current advice on using the web to promote your business it was packed with good tips. It also really felt as if Jonathan was doing his best to make a real difference to his readers rather than making himself seem smart as some authors can do.
Anyway, whether you are tempted to head out on your own, or are forced to by the current economic downturn, I can really recommend this book.