I interviewed with AirTran in February and have been wait'n for a class, too.  Some friends of mine who interviewed the week in front of me are now in the August 12th class.  
The latest news I have is that AirTran is planning on 2 additional new-hire classes "in the near future".  And since they're already looking for new applicants, I'm guess'n that the next classes could be mid September or early October . . .but that's just my guess.
I wish I knew more  . . but, don't we all  ! !
Keep the faith . . .and see ya in ATL.