Earlier today, we completed the update of the Halo 2 playlists as described in the weekly update. If you can still see Head to Head in your playlist selection screen in the game, you need to log out of Xbox Live and log back in until Head to Head is gone and the new playlists are showing up. Bungie.net is now also correctly showing the new lists. Have fun, and post any questions to Optimatch.
Please remember that for the next 24 hours, it will be possible for people to be playing with old playlists, which may make things a bit screwy. Most of it should be cleared up by this evening.