It won't be too hard for you to pick up on it if you've had that much experience with J2EE. I would recommend picking up a good book though, instead of trying to piece JSF together from a bunch of tutorials on the net. You should get Core JavaServer Faces by David Geary and Cay Horstmann.
They have posted a number of chapters from their book online:
http://www.horstmann.com/corejsf/
Just reading the online chapters should be ample to get you started on JSF.
CowKing
That's true. Core JavaServer Faces was written to JSF 1.1 specs. I haven't used 1.2 much, but my impressions have been that it is quite similar to JSF 1.1. I think 1.2 uses a Java 5 JRE and requires tomcat 6 (or a glassfish web server).
As far as the actual TLD's and API, I don't think it changed much. Most, if not all, work the same as in 1.1. There is a few more bells and whistles though. Like new attributes on the component tags.
The wikipedia article on JSF talks about a few of the new features in JSF 1.2.
http://en.wikipedia.org/wiki/JavaServer_Faces
Hope this helps.
CowKing