Picateers.com, offers free photo sharing. When parents buy from the website the school gets 25% cash back. They also have a portrait program that can be used for school special events. They school gets back 50%.
I'm active with the Music Parents Boosters at a high school level as their webmaster. We also have a few "Band Dads" who are great at digital photography.
I'm searching for Photo Sharing websites where we could upload digital photos from events (marching band competitions, concerts, plays, Renaissance feastes) and then parents can just click & buy the photos they want, BUT, the boosters receive a portion of the profits.
So far I have only found dotphoto.com, but they are really expensive!