YotoPhoto
YotoPhoto is a beta search-engine for creative commons and public-domain stock photography. At the moment it seems very very slow. A search for “mute swan” at +1500px one gave one hit, from Flickr. Which is strange, since Wikimedia offers a super selection of images. But YotoPhoto is a nice idea, and is sure to develop. Either that, or Google’s image search will soon add a ‘public domain only’ filter.