Not currently. Airplay does not at present allow you to stream from an iPhone to iTunes. Now, there will likely be a new version of iTunes coming out on Oct 4th and it is possible that is something they will add (and something I would like to see), but it isn't there currently.
There's an app called AirMusic that takes the music from the iPod app and streams it to WMP if you're using Windows. But you can't control it via the phone/ipod.