You have to get a program that can run gamecube discs but that usually involves inserting a mod chip into your computer which costs money, time, and generally isn't worth it. Another alternative is to download an emulator ("Dolphine" and "WhineCube" are two examples) and then download the iso to the game you want to play and either have the emulator run it, or for best results, burn it to a CD and run it that way.
QUOTE
There are devices to do this (that's how ROMs are made) but they're very expensive, likely 100+$
It doesn't actually work like that for gamecube. N64, Genises, SNES, NES, and whatever other consoles used cartridges utilized ROMs. Read-only memory (ROM) is an integrated circuit programmed with specific data when it is manufactured. That's why its pretty simple to make ROM's and emulators to play them. But the next gen of consoles used CD's and in order to transfer the data you have to make an ISO image of the CD, the transfer it, and burn it to another CD.