A guildy told me about a way to farm for herbs in Freya's room in Ulduar. It requires that Freya is not down but previous bosses have been downed. As i understand, it's a great way to farm herbs because it resets every 30mins. I imagine it would be easier if you have stealth but it can be done by any class.
Anyway, I found this video explains it a bit better (Not my video)
[ame=http://www.youtube.com/watch?v=tge7BNseJ4s]YouTube - Powerherbing Freya for Frost Lotus (no stealth)[/ame]
Have Fun!