Haven't done it, yet, but I'm hooked up with a lot of people who have and a lot of wannabees ... and I've done sections at a time from Amicalola to the south end of the GSNP at Fontana.
Here's what I recommend:
1. Join the AT-L and ask every question you might have. The AT-L is the email list-serve for ALDHA, Appalachian Trail Long Distance Association. You can find it and subscribe at www.backcountry.net. It's full of people who enjoy sharing their stories about their through hikes.
2. Join ALDHA. It's located at www.aldha.org. I think it costs $10 for a one year membership.
3. Go to the Gathering this October in Pipestem/Athens, West Virginia, the annual gathering of Appalachian Trail hikers. They'll have all the equipment shows and seminars you can ever use. Info about the Gathering is on the ALDHA web site.
4. Stay in touch with me: I want to learn all I can, too! I'm a wannabee and my high school daughter, a senior, wants to thru hike between high school and college ...

Hey Jack.
I thru-hiked GA>ME in. It feels like a long time ago. Anyways, I'm here, I'm listening... I don't know specifically what you want to know but I will keep checking this thread for questions that I can answer specifically.

Generally, being flexible helps quite a lot out there in making your hike what you want it to be. I definately wanted the experience of finishing -- that was important to me, so I suffered a lot through loneliness, pain in all shapes and sizes, and difficulty keeping up my body weight (i'm vegan -that made it a lot harder) and I got what I wanted out of it (and a lot more). Other people are looking for other things -- adventure, new directions, communion with nature, and when they feel they found them, the get off the trail.

If you are interested in trail culture at all, trail days is an amazing experience, and I definately felt fortified for having gone.

I know for me I had millions of questions about gear going out there. I can tell you what worked for me but I think for everyone, they started somewhere and eventually their system evolved into what worked for them. Some were happy to forgo the resting comforts (ie: hot food, warm bag) in order to maximize on walking comfort (and speed) but everyone found a balance they were comfortable with. Having money helps in a lot of ways -- your appetite and desire for a bed/shower will give no deference to your pocket book-- but it also helps in being able to adjust your gear. Anyways, ask me any questions you want and I will answer as best as possible.

No Whey
GA-ME
2000