Hoya75 is pretty much correct, although in basketball this year they are supposedly having a player from Knox Catholic and one from Knox Webb since they played in Notre Dame's region.
The Web site behind the games is www.stumponsports.com. Stump has a show on public access cable in the Chattanooga and North Georgia areas, hence the focus on those areas for the all-star games.
I haven't seen the rosters for the soccer game this year, Stump theoretically could announce them on his show tonight, which runs from 11 p.m. to 1 a.m. I believe the soccer game is June 16 at Ridgeland High School (in Georgia). I think the Times Free Press sportswriter who covers soccer (Jamie Lackey) has a large role in picking the Tennessee team, not sure who helps select the Georgia team.