Did you know that you can use “Invisible Mode” in the Google Talk app? This is not the web application, but the genuine standalone Google Talk app. You don’t have to use the GTalk applet that is embedded in Gmail any longer, and can avoid cyberstalkers with class and sophistication!

Here is the link to the version of GTalk you’re interested in – Google Talk Labs Edition:

http://www.google.com/talk/labsedition/index.html

I would recommend uninstalling the ordinary version of Gtalk first, otherwise the two will be installed side by side and become an annoyance.