Google Talk has released a new test version, but is seems they are only spreading the word through viral marketing. Through this link you can download the latest version (no April Fools Day joke, by the way).

New in this version:
– buddy icons (put your picture or avatar next to your name)
– chat themes
– contact card: when you move your mouse over a contact you see his/her details

(source: marketingfacts.nl)