That looks useful (well, not to personally to me, but I can see the attraction).

I think you are working in a fertile area. In my last trip I used the iPhone app Postino to send snail-mail postcards using pictures from the iPhone - it worked really well. So I can't help thinking "you need an app for that" :-)

I'd give your main site a try if only I could think of someone I want to snail mail!