Oops, my bad -- I didn't know OpenFlow 1.2 had been released because openflow.org hasn't been updated since early December. (I had it bookmarked and checked it occasionally just to see if IPv6 support ever got added.) The last I had heard/read, IPv6 support was just a proposed feature for a future spec...
Development and releases of the OpenFlow specification have been shifted to the Open Networking Foundation[1], so you can find the latest OpenFlow release (currently 1.2) over there. It has only come out recently though, so actual hardware & software support for the new version of the protocol is still quite young.
