Finally, there's some word about PvP in Diablo III as Jay Wilson tweets about a blog update incoming.
In typical Blizzard fashion, there is no date specified but it's safe to assume that it'll go live somewhere in early December. Having in mind the time frame between previous blog update posts and the release of the actual patch, given the current date (November 27th) one can speculate that PvP will indeed not be available until 2013.
@scaryrobots We'll be doing a PVP blog update very soon.Sorry to keep you waiting.
— Jay Wilson (@Angryrobotics) November 26, 2012