It didn't come out for the Xbox in North America, only the GameCube and PS2. In Europe it came out on Xbox and PS2 but not GameCube.
I got it for the PS2. A good game but extremely difficult. It has an insane amount of style and humor. I just wish I was better at it.
Their other game, Castle Crashers, looks great as well.
Oh, and it was originally a Flash game which you can play here