There's a basic set of iTunes controls at your WP7 phone's disposal, including volume, starting /stopping music, and searching by album, artist, and song, and a corresponding piece of desktop software you need to install to make the magic happen. It's compatible with both Windows (XP and above) and Mac OS (10.5.8 and above), so all you really need now are $1.99 for the mobile app and the overwhelming desire to control your playlists remotely.