Where can I go to find out more about backpacking?

I am planning to attend Outward Bound this summer and in a couple of years time I hope to travel the Appalachian Trail. However, I am currently only 15 and was wondering where I could go to find out more about backpacking. I have read a couple of books on it, but nothing is as helpful as experience. What items are important and which aren't necessities? Any ides on where I could find out information would be greatly appreciated.

Check out thebackpacker.com. You'll find lots of trail info, first-hand backpacking stories, basics, tips, and advice on gear.