Over a year ago, Google paid a billion dollars for a chunk of AOL, and probably the most exciting part of the deal was the announcement that Google Talk and AOL Instant Messenger would probable eventually connect to each other.
Finally, after 13 months of silence, Googler (and former AIM developer) Justin Uberti has sorta maybe confirmed that Google is still working on it, or at least that the official statement ("We are working actively on integrating AIM access in Google Talk.") still applies.
On the AOL side (connecting AIM to Google Talk), he's not sure if AOL's new management will make it enough of a priority, but notes AOL has a project in the works to allow Jabber clients (Google Talk is one) to access the AIM network, logged in under AIM screen names. It appears that AOL users should not wait up for AOL to add Google Talk access, but Google could (and might already be) do some cool stuff.
The best situation: Google Talk connects to the AIM network, letting Google Talk users add AIM users to their buddy list and chat with them. Google Talk also lets you log in simultaneously with your AIM screen name, getting your regular AIM buddy list and screen name. The idea: You log in under both names, at the same time, getting the AIM buddy list and not losing your old screen name, but slowly moving more over to the Google Talk network, since it lets you login both ways.