I've been collecting DVD cases for a while to do this project and I finally printed pictures and put it together last night. All I did was mount 4x6 pictures to some consturction paper (7 1/4x 4 7/8) and then slide it under the slip cover of the DVD case. I then (with the DVD case open) put a push pin through the plastic and closed the case. This made it really easy to hang them up so they would lay flat. If that doesn't make sense let me know and I'll try to explain it better or do detail pictures.
I'm very proud of how well it turned out. It's probably the only wall in my house that looks well put together.
*I did not create this idea I found it in a magazine somewhere*