Unfortunately, probably not. You would probably be better off trying to sale this stuff in your local newspaper. My reasoning for this, besides being a former Gamestop employee, is that the Gamecube is already cheap in stores and is getting very little resale value (especially since the Wii also plays Gamecube games); you could probably sale it yourself for alteast $45 if it's still in good shape or get possibly $15 for it trade in value (I know this sounds like a joke, but sadly it's probably true). As for the PS2, you can probably get a pretty nice chunk for it selling it yourself or trade in for about half. The handhelds on the other hand will almost definitely get you a decent trade in value, but still not as much as selling it yourself. Just hoping to lend a helping hand to prevent you from being ripped off with the trade in stuff, but if you give it a try do post if you will what kind of trade in value you get offered.
You can probably do pretty decent if you wanna go that route, probably get a good fund going for your Wii; maybe half. Just remember, things are pretty competitive there and you never really know until you give it a try. Hey, welcome to Wiichat too by the way...just noticed you just signed up. Hope to see you posting around.