From Rudy Huyn:
6tag is the most full featured Instagram app for Windows Phone.
Upload picture and videos on Instagram, apply filters, tag your friends, view posts on a map, etc...
2 designs: modern & polaroid
Customize your photos with one of several gorgeous and custom built filter effects.
Share your photos and videos on instagram
100% original instagram filters: XPro-II, Earlybird, Rise, Amaro, Hudson, Lo-fi, Sutro, Toaster, Brannan, Inkwell, Walden, Hefe, Nashville, 1977, and others.
Video recording with cut scenes
Linear and Radial Tilt-Shift blur effects for extra depth of field.
Instant sharing to Facebook, Twitter, Flickr, Tumblr and Foursquare, VK
Unlimited picture uploads on Instagram
geotag your posts
Interact with friends through giving & receiving likes and comments
Front & Back camera support
6tag is the fullest Instagram app for windows phone.