Several Apple Issued IDs can be AIM valid Screen Names.
These include @mac.com names issued under the.Mac service or later as a "iChat name" during the MobileMe era.
However the Passwords have to be 16 characters or less to work with the AIM servers.
Start here and the Manage Account link.
iCloud issues @me.com names will not work in iChat 5 or earlier
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.2)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad
"Limit the Logs to the Bits above Binary Images." No, Seriously