It needed a bit of extra time on the oven, but Xsan 2.2 is now available for download. You can find it in several flavors:

• Release notes
• Full Install Disk (all OS versions, it seems)
• Updater for 10.5
• Updater for 10.6
• Admin Tools for 10.5
• Admin Tools for 10.6
• Uninstaller

Or you can just use Software Update. (I can't remember a release of the full installer like this before. It is certainly a nice touch.)

Make sure you update your metadata controllers before updating clients. To be safe, make a backup of your MDC's /Library/Filesystems/Xsan/Config folder. And don't go enabling extended attributes until everyone is running Xsan 2.2.

[Update: Please note the interesting experiences in the comments below.]