You can transfer them not trade them. You do this by having two DSs, one with either white or black version, and one with D/P/P or HG/SS. On the DS with the en 4 game, press downliad play, and leave it there for now. Go to your DS with B/W and go to route 15 and find the poke transer lab (you can only do this after beating the elite four at least once) and talk to the people inside. The man will ask if you would like to poketransfer, you should say yes. When you say yes the poketransfer will begin. from there just follow instructions, and everything should go smoothly. If you need furhter instruction just ask.