Need help and creative ideas for a postcard collage?!?

I have travelled a bit and each place that I go I collect postcards. I like the fact that the postcard has a picture perfect picture already (in case my camera didn't capture it). I would like to be able to make something creative out of this to create a conversation piece as well as something that looks great on the wall. Please give me some ideas and perhaps a photo that I can refer to. I would really appreciate it. Please bear in mind that these postcards are different sizes. Also, I would like to be able to flip them, since I have written down exact dates and other info about the place. Thanks much