Google Talk (also known as Gtalk) is Google's instant communication service. There are already 3 official Google Talk copies:
Here is a pure JavaScript copy of Google Talk Client from izuz.net. It is considered a lot better that the one embeded with GMail. It uses the same UI of Google Talk Desktop Client, but is provided inside browsers. And it uses HTTP connections not XMPP connections, which means that it is firewall free or Websense free. Firewall or Websense may block you from using Gtalk/MSN by blocking certain ports, but it may never block port 80 or 443 (https port). So you are allowed to use your Gtalk by this pure JavaScript copy of Google Talk.
We strongly recomend you visit this page by Firefox 3.0+, Opera 9.0+ or Safari 3.1+.
Update: HTTPS is not necessary any more, as RSA encryption for your password is enabled inside this Gtalk.
Update: blog.izuz.net talks about web IM and you can report bugs or make feature requests there.
Twin projects: AOL Instant Messenger(AIM) on Gtalk UI and MSN Live Messenger on Gtalk UI
Zhou Renjian ( zhourenjian at gmail dot com ) @ Aug 27, 2008