There are obvious downloading issues, so apparently I'll have a more detailed report for you in about 11 hours. However, you can get started downloading your own PTR patch here (though if you could just wait until I've got mine that'd be great). The character copy function (there are apparently no pre-made characters available for copying) is overloaded by traffic and only gives a "server too busy" message.
However, lucky reader Mark is further along in the download process -- and managed to snag these screenshots of the patch notes. See page 1, page 2, page 3, page 4, page 5, and page 6 for the full patch notes -- or read on for a transcribed version (via Kyrra on the test realm forums).