The 5.1 patch note update blog can be found here:

http://us.battle.net/wow/en/blog/7922040

Don't forget to check out the 5.1 hotfixes blog too, since some important changes are included there:

http://us.battle.net/wow/en/blog/7922045

Oh, also: realms are live a bit earlier than anticipated. Go check out Landfall!

Your realms appear to be live. If you're experiencing any issues logging in, then you might want to head over to the Tech Support forum for assistance: http://us.battle.net/wow/en/forum/1011701/

11/27/2012 12:04 PMPosted by Wasabisauce

MMO-champ says it's there, but it's just not listed in the patch notes.

It didn't make it in for 5.1, but that doesn't mean that it's not coming.