Thanks for the quick reply.
I forgot to mention that this is what I see in the preview window when I am working with the ACR 6.1 lens correction plug-in. Click on lens correction, picture preview gets darker. Click off, image goes back to original exposure. Nothing happens with distortion correction.
I just remembered that I haven't actually output files comparing one with/without lens correction. D'oh! I'll do this, too.
I'll post some screen grabs / processed JPGs when I can get in front of my computer.