Some years ago, Google started a cooperation with AOL, so that users of the chat software Google Talk could also establish a connection to their friends in AOL Instant Messenger (AIM). Now, this integration has been enhanced.
It has always been possible to chat with your AIM buddies directly from Gmail, but you needed your own AOL network account for this feature. You don't need such anymore — AIM contacts can be added directly. This feature is not only supported by Gmail, but also by iGoogle, Orkut and Gtalk on Android smartphones. This works from AIM’s end as well: you can add Google users with their mail address.
As consequence of this new enhancement, the Google developers have removed the possibility to enter your AIM account at Google Talk. AOL has developed a little tool to make it easier for you to add your chat buddies in Google Talk.
Google Talk is based on the open XMPP protocol. Google has added VoIP functionality called Jingle. The service can be used with any chat programs, as long as they support the XMPP protocol.