It has begun. With the release of iTunes 8.2.1 (via TiPb), gut46 tells us, Palm Pre syncing with iTunes is indeed kaput. At least on this Pre user's Mac, iTunes sync isn't working after the 8.2.1 update.* According to Apple's surprisingly forthcoming release notes:

iTunes 8.2.1 provides a number of important bug fixes and addresses an issue with verification of Apple Devices.

We were wondering if this day would come after the back and forth between Apple and Palm on the issue. It's as-yet unclear exactly what method Apple is using to block Pre sync, but we suspect is wasn't easy. ...Which means we also suspect it might not be easy for Palm to turn it back on.

Well, webOS developers, a hard choice is in front of you. We already know you're awesome, now you just need to decide whether you direct your awesomeness at this cat-and-mouse game or focus on other things (like custom notification sounds).

For me, this news doesn't actually hit all that hard -- I already use doubleTwist for Palm Pre Media sync and recommend you do too until this issue gets sorted out. It may just be a long time, though. As noted in our comments - you also have the option of just not updating iTunes.

Update 1: plugging the Pre in does bring iTunes 8.2.1 to the front as though it wanted to work, but then iTunes simply doesn't show the Pre in the sidebar.

Update 2: Brent reminds us that Mac users may also want to check out The Missing Sync for Pre.