There it is, the new freebie from Apple which turns your iPhone or iPod touch into a remote control. It works with Apple TV and iTunes over the WiFi network to play, pause, skip and shuffle your songs stored in your iTunes library. You get access to playlists, album art (displayed in the Remote app), control over AirTunes speakers, and the ability to search your entire library. No video support apparently but free is free and 1.0 is 1.0.
Update: Looks like Apple has updated Apple TV to 2.1 with support for the new remote app, along with support for MobileMe. Get it via your Apple TV's Update Software feature.
Update 2: You can control playback of iTunes videos on your PC or Mac well -- a sceenshot of the video appears on the iPhone.