Earlier this year in Feburary, Google had introduces “Google Talk chatback badges“ for anonymous conversations with the visitors of a site. This feature is updated with new styles & more ways to display the badges. It’s now available by clicking on the “Styles” drop down menu when creating a chatback badge.
To create a badge, visit http://www.google.com/talk/service/badge/New or, if you are a Google Apps user, visit http://www.google.com/talk/service/a/DOMAIN/badge/New replacing DOMAIN with the name of your domain. Select "Hyperlink and status icon (no frame)" from the list of styles, click on "Update badge" and copy the code in a text editor. You should identify a URL that looks like this (the bold part could be removed to simplify the address):http://www.google.com/talk/service/badge/Show?