Fotopedia is a collaborative photo encyclopedia that hosts high-quality images whose subjects are matched to Wikipedia articles. For subjects that don't have a Wikipedia entry the community can build one. Some images are linked to a map so that you can see where the image was taken. You will find that some Fotopedia contributions are Creative Commons-licensed and others are not.
Fotopedia offers a variety of iPad and iPhone apps arranged around various themes of Fotopedia images.
Applications for Education
A few nights ago I browsed Fotopedia for a Creative Commons-licensed picture of a Zebra (it was part of a how-to booklet I'm building). While browsing through the images I realized that browsing Fotopedia could be a great visual way for students to discover information about animals. For example, when I was browsing the collection of Zebra images I was able to read the article about Zebras, click and see where the images were captured, and then jump into browsing images and information about where those images were captured. In the Zebra example I went from looking at pictures of Zebras to browsing pictures of Tanzania and reading about habit in Tanzania.