Here are some sites that I’ve found from reading technology integration blogs which look useful for your classrooms:
Freestock photos at Freerange.com: Need a picture for a project/PPT/other instructional need? Use of their pictures is pretty wide open with a few exceptions. You can read the license restrictions here : http://www.freerangestock.com/licensing.php
Glogster: Mix graphics, photos, videos, music and text into slick Glogs. Although I have not explored this myself, it looks like it holds promise for projects (I’m wondering vocabulary review for Science, Social Studies, Math, ad infinitum).
Pixisnap: Create photo mosaics and Polaroid pics in a snap with Pixisnap!
Turn your lifeless picture to awesome photo mosaics or cool Polaroid
and make them your desktop wallpaper or Myspace background.
Pics4Learning: Need some safe pictures for students to use for PPt projects, PhotoStory, or the like?
Speakaboos: Online childrens’ stories for K-3. Some reviews mention that there are empty spots with graphics, but well worth the time to look (seems that it’s free). Great for reading teachers.
New York Public Library’s Digital Gallery: NYPL Digital Gallery provides free and open access to over 640,000 images digitized from the The New York Public Library’s vast collections, including illuminated manuscripts, historical maps, vintage posters, rare prints, photographs and more.
MOOM: Museum of Online Museums has online exhibits covering a vast array of interests and areas.

