Remote control of my Mac is one of the things I thought Apple would be including with the iPhone...and perhaps they will yet. Until then, there's Phone Home, a free program (donations accepted) which runs on your Mac and allows you to remotely control Keynote, DVD Player, and iTunes, with more promised. Phone Home runs through a nice browser-based interface on the iPhone, and requires a quick setup. It's not exactly speedy while downloading my large song lists, but it seems well up to the task of skipping tracks, adjusting volume, and scrolling through your playlists and tracks. Very very cool.
