A pre-release version of iTunes 7.7 includes this little gem:
Use iTunes 7.7 to sync music, video, and more with iPhone 3G, and download applications from the iTunes Store exclusively designed for iPhone and iPod touch with software version 2.0 or later. Also use the new Remote application for iPhone or iPod touch to control iTunes playback from anywhere in your home — a free download from the App Store.
The real question, however, is whether this will work with Apple TV. Desktop iTunes might be a “nice-to-have” but an Apple TV remote would be amazing.