LIFE Magazine has added many of their photographs to the Google Images database. You can enjoy (and copy for your own personal non-commercial use.) There are some REALLY great high-resolution images and hours of time-wasting fun.
If you do a search for “WACS”, “WAVES”, “SPARS”, “Female Marine”, “American Red Cross”, “Women Air Force”, “Army Nurse”, etc. you can see some really great images from the 1940s-now. (Plus, if you search for “WAVES”, you can also see an image of Frank Sinatra waving.)