So I haven't posted much since we've been pretty crazy at working trying to wrap up on Uncharted 2...I just finished up this tool recently that I thought I'd share.
It might be a little confusing from the video, but basically you always have the FK controls selected and you're always keying them. So in essence you're never actually in IK. This just lets you pose and FK arm with an IK tool/context.
Let me know if you got any questions....
Here's a sticky post of my reel - look in the previous posts for the full posting: Rigging Reel