Maybe it's there for a long time but I never noticed it before, at the bottom on the page there is an translate widget wich in my case says 'Vertalen' to translate the page to Dutch.
I also noticed the button in Internet Explorer 6, so it's not from a toolbar or something like that.
http://dev.chromium.org/getting-involved/dev-channel |
that is a feature of google sites. you can also added it to any website using a smal javascript
if i have time later, i will search the google blogpost |