I am obsessed with the instagram app on my iPhone, and I use it all the time. I never really do anything with the pics though. I'll create a phone background, or use the pics on here, but I never print them or anything. I found this awesome site called StickyGram that turns your instagram pics into magnets!
StickyGram prints your instagrams on a 50 mm x 50 mm flexible magnet. They come in packs of 9, and cost $14.99 + free shipping. These would look so cute on the fridge, locker, file cabinets, bulletin boards, where ever you can stick 'em.