Instagram Badges is a WordPress plugin by Sparanoid that adds Instagram badges to your WordPress blog. The author says this plugin works fine with multisite enabled WordPress (aka. WordPress Mu).
Instagram is a free photo-sharing program and social network service that enables users to take a photo, apply a digital filter to it, and then share it with other Instagram users they are connected to on the social network as well as on a variety of social networking services
Download: http://wordpress.org/extend/plugins/instagram-badges/