Apple will probably have java or flash games on its iphone or ipod touch, and the games will be available on download for like $5 off the itunes music store. Perhaps it can liscense old ROMS from different 3rd party companies, but I doubt they will directly compete against the Nintendo DS or the PSP.
It will probably be touted as an iPod that can play games (as it is now), but not anything completely dedicated to playing games.
As for consoles, I can see the AppleTV easily becoming a trojan horse for games. But again, any games from Apple via the AppleTV would probably be simple java or flash games available for download on the iTunes Music store.
My speculation is that it won't displace Wii or PS3 or Xbox games, but it probably will put dents in the DLC market (i.e. XBLA/WiiWare)
