The Nokia Lumia 900 features a 4.3 inch display, 8MP camera, LTE connectivity and is powered by a 1.4 GHz processor. Nokia plans to set their Windows Phones apart from the pack and one way they plan to do this is by introducing exclusive applications which will be available to Nokia Windows Phone users. Two of these apps which are currently available in beta are Nokia City Lens and Nokia Transport.
Nokia City Lens is an augmented reality app which shows you information on objects and landmarks through the 8MP camera. You can tap on a device you see to show you information about it.
source - TheNokiaBlog