For the druids who want to tank, this is the spec I used on Nostalrius PvP:
http://db.vanillagaming.org/?talent#0ZxoxscrdxVxf0xo
Take the two points from "Blood Frenzy" and put them into "Feral Instinct" if you are having trouble keeping threat.
I had a blast running this spec in both PvE and PvP. Your primary focus is on tanking with enough Resto to be able to heal in situations where your tanking isn't needed, albeit not as good as a true resto druid. Gear plays a big part in playing either the tanking or healing role in this spec, so be wary.