Apple continues to provide the least amount of Bluetooth support needed to trick you into buying their stuff. From the support article iPhone and iPod touch: Supported Bluetooth profiles:
iPhone and iPod touch (2nd generation) support pause, play, and stop for AVRCP
So with the nifty Kensington LiquidAUX Bluetooth that I just added to my car, I can play music with my new 3G S but I can’t skip a track without pulling it out of my pocket.
Lame.