I were trying to convert gaim into transport last summer. I have stuck at the subscriptions transfer and the project died. Though it were able to transfer messages and presences and it the whole contains a good (I hope) framework to achieve the goal.
Now I have decided that I probably will not do it anymore but may be someone will be interested in looking to it or trying it. For these ones here is the link to instructions: http://www.penza-gsm.ru/snake/pyGAIM-t.git/README.git -- Respectfully Alexey Nezhdanov
