Headset (not headphone) adapter
Watching a friend play with his spanking new iPhone today with a headphone adapter that has a built-in microphone for taking calls, I had to wonder why somebody doesn't make a headset adapter. That is, an adapter with both headphone output and microphone input jacks, to be used with PC headsets. A noise-cancelling microphone boom would work a lot better than those clip-on mics. So why not? Is the signal level wrong for the iPhone? I can't imagine that itty bitty microphone in the adapter being strong enough to output a line-level signal, so if it's microphone-level, the iPhone should be compatible with PC headsets.