Probably never, considering that the Gamecube's almost permanently dead.
Seriously, how many games will the Gamecube see in 2006? The
release list I've seen shows a few so-so titles, and a bunch of titles like Spiderman and X-men which are clearly just a cash-in from movies. Every developer is preparing for the Revolution, so there's no time for the poor old Gamecube now.
In comparison to the xbox and PS2's release list, it's quite
patheticdepressing. It's possible that there will be a 2D, or 3D (
lol) Donkey Kong game made for the Revolution, and it'll be used with that.. uh, Revolution remote. So I guess it's a novelty all around.
Jam it back in, in the dark.