I wrote a post on this iPhone app a while back, but it has changed so much since then I thought it deserved another post.
This camera app emulates the little toy plastic film cameras from back in the day. While the app store has plenty of apps that will process your camera phone photos to look like old polaroids, or light leaked photos. This one is by far the best and most fun. It takes photos in square format, and the interface of the application is that of an old 120 Holga like camera. You have a bunch of different film, lens, and flash combinations that give your photos a unique look. But by far my new favorite addition to this app is the ability to print directly from the application. That is way cool. They are fast on getting you your prints as well. I ordered some Saturday morning and I received my photos by Monday afternoon. The quality of the paper is kinda cheap, and definitely not high end prints but cmon these are coming from your phone camera.
I have heard some photographers critique this app, and others like it because they feel like now everyone thinks they are a creative "photographer". I think it's great that it gets people taking pictures, posting to flickr, and facebook. I have always felt that the medium in which you create in is not important as long as you enjoy creating. You don't need to have a super decked out DSLR to take great photos. As a matter of fact some of my most viewed photos on flickr were taken with my little $200 5 yr old Canon powershot. It's all just a matter of playing around and having fun with photography.
Anyway, I digress. The hipstamatic iPhone app is a must have. Hopefully it will Incite the creative in you and get you playing around, and now with the printing functionality making prints as well.