It really is kind of amazing that Instagram has shot past two million users in just a few months with only an iPhone app. No Android app, no website, no real third-party support. But starting today, that changes as they're finally ready to unveil their API. And they already have some pretty nice implementations right off the bat to show what it can do. Co-founder Kevin Systrom says that it would have been easy enough for them to implement a simple API early on, but they didn't want to do that (that's why you may have heard about one developer getting unofficial access shut off ). Instead, Instagram decided they wanted to make an API that was both massively scalable and provided a realtime feed of everything going on across the service. Today, they're unveiling this realtime API for four different elements of Instagram: user photos, tags, locations, and geographies.