iTunes 8 to our Airport Express last night when -- poof -- "-3256 Unknown Error Occurred." This cryptic error, along with another under the equally descriptive name "-15000," has been keeping iTunes 8 upgraders from using their Airtunes on remote speakers. Turns out the issue is one of Firewalls and Firmware. The solutions come from users at Apple's discussion boards. Basically, you need to either turn off your Firewall and / or allow iTunes to accept incoming requests or update your Airport Express to the latest (7.3.2 as of this post) firmware version via AirPort Utility 6.3. Meanwhile, Windows-based iPod touch users are seeing Blue Screens of Death when plugging in their players due to some other undocumented problem. The solution there looks to be a reboot with the touch plugged in to force the system to recognize the device, run a sync, and turn off photo syncing (not the most elegant solution, clearly). Let's hope Apple at least updates this with something more descriptive than "-3256" in the future. Customer service reps at Apple say they're aware of the problems and are working on a fix.
Read - iTunes 8 & Airtunes/Airport Express
Read - blue screen comes up when plugging in ipod
[Thanks to everyone who sent this in]