Here's your chance to get as many Eevees as you like. Once you have opened up the Elite Four Battle, you can just start from there. However, it's rather risky and may corrupt your saved game file if not done correctly. Trade the Pokemon to be cloned, and have the other player select a Pokemon that he or she does not care about. Trade them, and make sure the player receiving the bad Pokemon can see the other player's screen.
Timing is important.
Both games will have the same good Pokemon when they are turned back on. Keep an eye on our frequently updated IGN codes pages . Simply click on the image to the right to check them out.