Skype Journal has a post about Google interoperating with AIM this year. The post contains a link to a post by a Google employee (who appears to have previously worked at AOL) , which links to a competition at TopCoder (that appears to be sponsored by AOL) to develop an XMPP - AIM gateway.
The competition doesn't include voice/video integration. I wish AOL would just release the AIM protocol specs - then they'd get an XMPP-AIM gateway for free that would probably include voice/video integration. XMPP-AIM gateways already exist for free, but can only use the features of the AIM protocol (called OSCAR) that have been reverse engineered.
My own analysis of how AIM Phoneline works leads me to believe voice integration might be possible - it uses SIP (in a slightly odd manner) and GTalk has already been federated with SIP providers. It's a shame that AOL have chosen to base their latest voice product on an open protocol while still keeping their users in a walled garden.