Copying Console Games is illegal. PERIOD.
Sorry but open up your manuals and read the EULA they have in them. I have no games which are not on the PC which mention being legally allowed to copy the game even for backup means.
And I don't have a small library of games here.
Q- Can you copy Gamecube games?
A- Erm... This is still out on debate actually. Although yes I can say you can copy a Gamecube game from your GameDisc to your PC.
There are NO working emulators to test if it actually works, and there is currently no way to put it back onto the GameCube itself.
I doubt you will ever see Pirated GameCube games.
The format used is Panasonic DVD-RAM, however it uses an extra layer which causes PC drives (even those which support the format) not to read it, and the GameCube requires that hidden layer.
The only way to do it would be to heavily modify your GameCube to accept standard DVD-RAM discs.
Problem with that option is actually, well i'll let you look up the price of them.
For the PS2 & XBox, yeah you can... But you need a Modded Console.
Copied games won't work on them, I've tried this a good number of times. I could explain a way around it, but if you want to know find out for yourself.
Personally i back up all of my games because i think my brother plays frisbie with mine due to the number of scratches they get.
Oh and if you have the chance I'd STRONGLY suggest upgrading your PS2 DVD Lazer. Even if you don't plan to copy games for backup means, the damn things lazer is some of the most poorly constructed hardware i've ever used. (and i've used SiS)