ARviewer is a FLOSS mobile augmented reality browser and editor that you can easily integrate in your own Android applications.
The browser part of ARviewer draws the label associated with an object of the reality using as parameters both its A-GPS position and its altitude. The system works both outdoors and indoors---in this latest case with location provided by QR-codes. ARviewer labels can be shown through a traditional list based view or through an AR view---a magic lens mobile augmented reality UI.
ARviewer is not only an AR browser that draws labels that others have created over the objects of the reality perceived through the camera of the mobile. ARviewer can also be used to create and upload content, enabling throwdown applications such as FourSquare or social game applications to create and associate labels with a latitude, longitude and altitude from the mobile.