Colosseum has an in-game trade center in Phenac City, and you can access it after you defeat... I don't know, Colosseum's equilavent of the Elite Four and the bad Dr. Robotnik ripoff. You just need a GBA/GCN Link Cable, and you can trade between RS (and FR/LG). I've done it and I've gotten my first Kingdra and Machamp.
you mean um, uh, Evice (nascours boss
) you won't believe who he is (
) nobody ruin it, please.