The FlickR Commons is a group of Library of Congress photos for which no copyright restrictions are known (several hundred color photos taken during the period 1939-1944). That’s right, boys and girls- no copyright restrictions! So if you’re writing (or have previously written) a family history or other genealogical tome, and could use some interesting, no-cost photos, this may be your lucky day! Go here for details, and to browse photos:
BTW, they want you to add your comments to photos you view, as part of an experiment in social tagging (folksonomy). Comments I examined were the usual feast or famine mixture of very insightful / wise guy type remarks.