I've just started a Death Knight (Tynnan) to run while my rest regens on Kirek. Does anyone have any good PvP strategy for these guys? PvE seems to be very forgiving with these guys but, I just get owned vs other players.

I guess that would depend on what spec you are.  I always found that, as blood, my DK was pretty much indestructable in pvp.  Your dps heals you.. what more could you need? :)