From Instagram, Inc:
Instagram is a way to share your world. Pick from one of several gorgeous filtered effects to breathe a new life into your mobile photos. Transform everyday moments into works of art you'll want to share with friends and family. Share your photos in a simple photo stream with friends to see and follow your friends' photos with the click of a single button. Every day you open up Instagram, you'll see new photos from your closest friends, and creative people from around the world. Features include free custom designed filters and borders, lux works it's magic by making your photos more vibrant and brings out details in your photos you couldn't see before, linear and radial Tilt-Shift blur effects for extra depth of field, instant sharing to Facebook, Twitter, Tumblr, and Foursquare, interact with friends through giving and receiving likes and comments, and full front and back camera support.
What's new in this version:
Version 3.4.2 includes bug fix and improvements.