If you are currently one of the 30 million users of instagram, then you are an iPhone user as they only allow photo sharing from their mobile app (not the web) and, until recently, they only had an iPhone app.
If you are an andriod user who has been anxiously awaiting a version for your phone, the wait is over as long as you are running version 2.2 or later of the os.
Instagram is a free photo sharing app that lets you quickly take and share photos on the go. They have a standard set of filters you can apply to jazz up your images. And, like all good apps these days, it has simple social features that allow you to like photos, comment, and even follow other instagrammers.
And if you have never heard of instagram, you might want to download the free app and give it a try. It is another example of how developers and entrepreneurs can turn something as simple as filtering and sharing a mobile photo into a very addicting habit.
As pointed out by a recent gigaom article, their site is getting about 300 million page views a month and that will only expand now that an andriod version is available.