I'm scheduling the deployment of Bukkit v1.1 for probably Saturday at noon, MST. I'm in the middle of helping my folks with some renovations, so my time has been very limited.
Josh alerted me that Bukkit released a v1.1-compatible update as of yesterday. I haven't had a chance to test it yet, but I'm expecting that we'll be deploying it Friday evening sometime. Since the update will require some downtime of the Minecraft server instance, we may also take the opportunity to update a number of plugins. Be aware that the updates will depend on the results of our tests and may be delayed until this weekend.
Since there's a couple of you who've accidentally updated Minecraft to 1.1 the day it was released and are likely using my hack of copying over an old minecraft.jar, you'll need to essentially remove the hack and restore Minecraft to such a state that it can be updated. You should be able to do this by removing the [tt]version[/tt] file in the [tt].minecraft/bin[/tt] directory.
To remove the version file in Windows, type [tt]%AppData%\.minecraft\bin[/tt] into either the run dialog or the "search" text field from the start menu and press enter. This will open Windows Explorer to the Minecraft [tt]bin[/tt] directory, and you can remove the [tt]version[/tt] file from here. If this doesn't work, you may need to delete both [tt]minecraft.jar[/tt] and [tt]version[/tt].
Linux and OS X require slightly different directions, but I don't think that's a concern in this particular case.