I've been using Gatherer and GathererDB to help me find ore and herbs. Unfortunately the authors blew away all the data in GathererDB because of all the changes in Cataclysm - and they've since released only one update, way back in mid December, when very little data was available.
However, another fellow has begun extracting the WoWHead data and putting it into a new GathererDB database. Here are some links:
Lloydpick's GathererDB WoWHead Updates - Here you can download a more up-to-date GathererDB database.
GathererDB on WoWHead - This is the comments section where I found out about the above download.
I Installed Lloyd's updates this morning and, while the density of nodes is nowhere near what it was with the old, pre-Cata database, there does seem to be quite a few new ones. I think it's worth doing the update.
Back up your WTF folder first, though, just in case!