Infact I have to add this as I just thought of it.

2 books that I absolutey 100% insist you buy if you are thinking of running a small business is

Robert Kiyosaki - Cash flow Quadrant
Robert Kiyosaki - Rich Dad's guide to investing

They can be read seperate, but if you are getting one, I suggest getting both as they refer to each other often. They are insanely motivational and just give you a thousand reasons why starting your own business is the ONLY way to go if you want to free yourself up financially at any stage in the future...
It answers so many questions that you didn't even realise you needed answering.