A new Sony PSP commercial shows off 7 new colors. Of course you have the standard white and black, but you also have the green, red, yellow, silver and blue models. Judging by the voiceovers, it may be Japan-only. But until we have official confirmation by Sony, we can assume these colors will be releasing in North America.
http://www.viddler.com/explore/Joystiq/videos/745/5.532
http://www.viddler.com/explore/Joystiq/videos/745/5.532