The official patch notes have been updated for the Patch 3.1 PTR. You can see a complete list of changes after the break, or take a look at the fully updated notes.
This update is much more substantial than the one we posted a couple nights ago. Nonetheless, it has been added to our Patch 3.1 patch notes archive. Via the archive you can also view other iterations of the patch notes to see how things have changed.
As always, these notes should be considered incomplete (it's in bold because we can't say it enough). A number of things that are on the PTR are not reflected in the patch notes, and several things that will eventually be on the PTR aren't in the notes either (many of the class changes, for example).
Check out WoW Insider's Guide to Patch 3.1 for more information.