I'm doing 3v3s on my priest in my raiding spec atm. I know my team can do better if i spec more for pvp. I am running with a MS Mace spec warrior and CB/ Seal Fate/ ShS rogue. Please use any talent calculator and post the spec here if you can.
http://www.wowhead.com/?talent=bxxRuhgtMckzfVzo That is a pretty cookie cutter priest build with eight points left up to your preference. Feel free to ask any questions you might have via this thread or PMs.
I used to use http://arenajunkies.com/talents/priest/42_19_0/ but now I use http://arenajunkies.com/talents/priest/34_5_22/ and oh my god the mind flay spec is soooooooooo much fun. I would use the top one if you dont have lots of resi.