Through Matt Cutts twitter <- googleos
http://googlesystem.blogspot.com/2009/06/find-creative-commons-images-in-google.html

[Moved from "Google adds Creative Commons to image search" – Tony]

"Google has added a Creative Commons filtering to their image search. With this filter Google wants to make it easier on those who dont want to be bothered with copyright issues."

http://www.searchcowboys.com/google/666

[Moved from "Google adds Creative Commons to image search" – Tony]

Thanks for quoting the source.

Ionut, I missed your post so that's why thought it was new :-). I see indeed that searchcowboys just took over your post, without source, hmm.