Instagram has taken the iOS world by storm, giving iPhone owners the ability to neatly tweak and adjust photos before sharing them with the world. It's a painfully simple concept, but it has caught fire like no other. Also, it's free. And now, it's on Android. Worldwide, there are certainly more Android smartphones in use than iPhones, and Instagram's servers are bound to feel the pressure when potentially millions of new users sign up. It's hard to believe that an app like Instagram has remained off of Android for this long, but that's now changed. It's free to download, works on all Android 2.2+ smartphones (not tablets, at least not yet) and includes the same filters as on iOS. What are you waiting for?