I thought I'd try this seeing as how it's my forum. I don't expect it to work, but.... maybe it will.
Currently there are numberous emulators for gamecube and ds. The only problem is, none of them work 100%. At best GC emulators work at 10%, and ds emulators somewhere around 20%.
This may change with time, but for now any emulator you download will not run games.
Consider this a warning. Because I've answered your question about why your gc and ds emulators aren't working, I don't want to see new topics called 'why isn't my ds emulator working?', ok?