How do I become a personal trainer when I grow up?

If anyone out there is a personal trainer, I’d love to find out how to get started.  Which books to read, which ones to avoid?  What certification should I set as a goal?  Right now, I’m just doing searches on the web for popular books, book reviews, etc.

All i want to achieve right now is to be able to successfully “train” a couple of friends for practice.  I’ve had some people say they’re interested, but i'm betting they are just being polite =)