The GHIP mountain bike trail was built for the 1996 Olympics. The trail was built to race not for sustainability so in the past 14 years there has been a lot of wash out. However SORBA Atlanta has been hard at work. They have been doing reroutes around badly worn areas and have more planned in the near future. The trail is a great technical trail with fast, fun downhills, some gut busting uphills, a few rock gardens and a new ladder bridge over a fallen tree. There are two sides to the trail: the dirt side and the granite side. The trail does cross horse paths so keep an eye out for them. SORBA also has some beginners trails in the works. It is a great place to ride with great scenery and nothing but the sounds of nature, once you get back into the trails.
From I-20, take Exit 82 "Georgia International Horse Park." Go North on 20 (or East on 138) for approximately 5 miles. There will be signs to turn right for the Horse Park. Large gravel parking area on the right. Pay $5 at the trailhead kiosk.
http://www.singletracks.com/item.php?c=1&i=580