Also threw the lineart up here
From front to back we have Kid Flash (Wally West), Robin (Dick Grayson), Aqualad and Superboy.
The characters in the background are, from left to right, Batman, Superman, Red Tornado, and Black Canary in the top. In the bottom row we have Artemis and Miss Martian.
Watch the show!
EDIT 2 Jul 1, 2011: FINALLY got around to revising some of the stuff in this pic that bugged me! such is the joy of revisiting an old picture lol.