Beaware when downloading games like Pokemon HeartGold (U) and SoulSilver (U). The games have Anti-Piracy so that they will freeze whilst you play. A lot of people are triyng to make a patch so that the games stop freezing. Other games include Sega All-Stars Racing (U) and there is a saving bug on WarioWare - DIY (U).
Romulation has more information:
www.romulation.net (http://www.romulation.net)
Games with Anti-piracy, I suggest you purchase the games!