Just seen:

WIKITUDE World Browser presents the user with data about their surroundings, nearby landmarks, and other points of interest by overlaying information on the real-time camera view of a smart-phone.

The information is drawn from Wikipedia and other sources. This to me has obvious applications in overlaying landscape archaeology information into the landscape… if it works. Has anybody used this?

I note also that Wikitude provides an API for building your own augmented reality applications:

The WIKITUDE API is a powerful application programming interface which allows for the open development of markerless AR experiences, providing developers with the tools to either create their own android augmented reality applications, or enhance their existing Android applications with an AR camera-view engine.  [more]

The Horizon 2010 report has a whole section on AR:

While the capability to deliver augmented reality experiences has been around for decades, it is only very recently that those experiences have become easy and portable. Advances in mobile devices as well as in the different technologies that combine the real world with virtual information have led to augmented reality applications that are as near to hand as any other application on a laptop or a smart phone. New uses for augmented reality are being explored and new experiments undertaken now that it is easy to do so. Emerging augmented reality tools to date have been mainly designed for marketing, social purposes, amusement, or location-based information, but new ones continue to appear as the technology becomes more popular. Augmented reality has become simple, and is now poised to enter the mainstream in the consumer sector.