Go to your user page and click on the Forum and Comment Settings tab. You'll need to go to the old upload page to get any old avatars you need and then reupload on the new page. It's a bit of the a pain in the ***, but once you've got them switched over it's actually easier to change avatars.
I really need to add that to the FAQ, just haven't gotten around to it. Kirby has an image even to show how it's done. (I am going to steal it! MWHAHAHA)
Thx for the info on the avatars... although it was a bit confusing - I finally figured it out. Don't think it was your fault for making it hard to understand, rather I think the process on Alla's to change an avatar - as you said - is a real PITA... Thanks again - got enough info off your post to steer me in the right direction