the author of this app says:
Instagram is an amazingly fun & simple life-sharing app for your iPhone. Snap photos wherever you go to show the world whats going on in your life. Follow your friends photo updates as they move through the world. Select from photo filters that transform regular ol photos into works of art youll want to keep around forever.
Compatible with iPhone, iPod touch and iPad. Requires iOS 3.1.2 or later.