We just confirmed it on our own machines: iTunes 8.2.1 breaks Pre syncing. Apple warned that they may cut off the sync, and Palm said it would be a direct blow to their users. Direct Blow, she is a'here. Updated
Obviously if you're a Pre user you should not update to the latest iTunes. Not, at least, until Palm strikes back with some kind of firmware update to enable syncing again. It's not like 8.2.1 has all that many new features either, so you don't really need to update. [Pre Thinking]
Update: Here's Palm's official statement:
Palm's media sync works with iTunes 8.2. If Apple chooses to disable media sync in iTunes, it will be a direct blow to their users who will be deprived of a seamless synchronization experience. However, people will have options. They can stay with the iTunes version that works to sync their music on their Pre, they can transfer the music via USB, and there are other third-party applications we can consider.
Update 2: Here's Apple's official statement to Businessweek:
iTunes 8.2.1 is a free software update that provides a number of important bug fixes. It also disables devices falsely pretending to be iPods, including the Palm Pre. As we've said before, newer versions of Apple's iTunes software may no longer provide syncing functionality with unsupported digital media players.