A couple of questions/concerns that have come up lately;
How much space do we have to camp?
About 10 ft x 10 ft. It's the width of your vehicle (+ half the distance to the next one) by 10 - 15 ft deep. There aren't lines painted on the ground or anything like that, make nice with your neighbors (really, very first thing after you get out of your car, walk over, introduce yourself, offer them a beer, whatever. It will pay dividends, plus it's the personable thing to do), it should be fine.
What's the story with Tent Only?
Tent Only is an increasingly small area very close to Centeroo where you can haul your stuff and set up your campsite. You have to carry (on foot) your gear over there. It has gotten more popular every year, and every year they make it smaller (got to make room for "Groop Camping" and "Tent City", etc), so it has gotten somewhat packed. It is the only place at 'roo that I camp; the best scene at the farm. If you are interested in it, go over to inforoo.com forums and check out the threads about it.
Help, I've never camped or anything like that!
Camping isn't hard, especially at a festival like Bonnaroo. Some important things in no real order. Practice setting up your tent at least once at home before going to 'roo. This is my 9th year going and I still do this; I've saved myself from the "oh crap, the tent stakes are still in my basement" moment. Water, water and more water (did I mention drinking water?). Comfortable shoes are an absolute must. You'll do more walking than you expect at 'roo. Sunscreen obviously.