Google, the ubiquitous Web search company that shook up the Web-based email world a year and a half ago by offering a gigabyte of permanent email storage with its free Gmail service, last week staked a claim to the instant messaging territory with the announcement of its free Google Talk service.

<http://talk.google.com/>

Based on the open Extensible Messaging and Presence Protocol (XMPP) developed by the Jabber open-source community, Google Talk offers text-based instant messaging using any Jabber-compatible client software, and voice chats with the official Google Talk software. So far, Google has released a Google Talk client only for Windows 2000 and XP, but they point to third-party Jabber clients for Mac and Linux users. For instructions on how to use one of these programs to chat with Google Talk users, click the client's name in the list linked below.

<http://www.xmpp.org/>
<http://www.google.com/talk/otherclients.html>

Apple's latest iChat, released with Mac OS X 10.4 Tiger, and the free Adium multi-protocol chat client both fully support text chats with Google Talk users. Fire, another popular, free multi-protocol chat client, works with Google Talk in the 1.5.3 version, but as of this writing has some bugs in defining new contacts. An upcoming 1.5.4 release of Fire should resolve the remaining Jabber issues. Currently, there is no Mac solution for Google Talk's voice chatting feature.

<http://www.apple.com/ichat/>
<http://www.google.com/support/talk/bin/ answer.py?answer=24076>
<http://www.adiumx.com/>
<http://www.google.com/support/talk/bin/ answer.py?answer=24075>
<http://fire.sourceforge.net/>

The Jabber Software Foundation and others have pointed out that Google Talk leaves out one key aspect of the Jabber concept, inter-server chatting, which allows users on different, private Jabber servers to communicate with each other. Google promises to work on server interoperability, but in the meantime, users on separate Jabber servers won't be able to communicate with Google Talk users any more than they can communicate with AIM users.