I would check out Whiteblaze.net. There is a lot of great information there from experienced AT hikers (and wanna/gonna be's).

Also look at Trailjournals.com and read a few of the journals of people that have done the time. Look for journals that have lots of read entries. There usually the best.
One of our favorite authors is a guy by the name of Bearpaw. <img src="/forums/images/graemlins/smile.gif" alt="" />
I can recommend a few others I've read but prefer to do that in a PM (private message).

From these journals you can find out a lot of information about the area you want to hike, but you have to dig through to find it.

You can also check out www.appalachiantrail.org. You can order all the information you need about the various sections of the AT.

Happy Trails!