Both Jedi-SDL and Pheonix Engines would be perfect choices for a pong game, I would think. Both are 2D, both do everything you need (as far as I know )

OpenGL not support sound input? I dunno what you mean by that, but you could play an mp3 song in Opengl every time the ball hits something, if you wanted... or you could stick with the bland ol' beep.

Edit: Read the rules too... your post will be deleted if you don't.