6tag for Windows Phone is the closest thing to having Instagram on Windows Phone 820
A new third party Instagram client has appeared in the Windows Phone Store that offers Windows Phone 8 users a complete Instagram experience, including video uploads. 6tag, formerly known as 6tagram, is the first 100% API compliant Instagram app for Windows Phone 8 devices. Other third party apps had to either specialize in uploading pictures, while others could only view Instagram member's sites. Then when Instagram added video to the mix, it created another wave of limited third party apps.
6tag, which will eventually be available for Windows Phone 7.x models, offers original filters like XPro-II, Earlybird, Rise, Amaro, Hudson, Lo-fi, Sutro, Toaster, Brannan, Inkwell, Walden, Hefe, Nashville, 1977, and more. You can record video and cut scenes with unlimited picture uploads and sharing to social sites like Facebook, Twitter, Flickr, Tumblr and Foursquare. Yes, you can hand out "Likes" and make comments while geotagging your posts. You can even use the back and front camera on your phone. 6tag has just added NFC sharing which allows users of the app to share Instagram pictures to Windows Phone or Android users via NFC.
6tag is free to download although it will take a $1.29 in-app purchase to eliminate ads while an in-app purchase of $1.49 lets you upload video. Everyone gets one free video upload to test out the app. You can find the app in the Windows Phone Store.
source: 6tag via WMPoweruser, WPCentral