This app will take a picture of your choosing (that you took on your phone) and send it as a postcard to anywhere for $0.99! That is just too cool! I just sent one to myself so I can see the quality, etc. I will update you when I receive it. You can even send via home computer but I'm thinking the postcard thing is much better when you are actually out on vacation and sending one home for the people you left behind.
Check it out: http://postagramapp.com/