Convince them to switch to XMPP instead. Get an account from Jabber.org, and install Pidgin or Adium. Then they can talk to anybody else with an XMPP account on

Convince them to switch to XMPP instead. Get an account from Jabber.org, and install Pidgin or Adium. Then they can talk to anybody else with an XMPP account on any domain, which includes Google Talk users until that service gets nuked.