Great use of mobile marketing

The Museum of London has launched a free iPhone app called StreetMuseum, which guides users to more than 200 historic sites in the capital, where, if they hold up their iPhones, they can see a photo of the past emerge as an overlay across the present scene.

What a fantastic use of smart phone functionality - its truly mobile, feeds geo-specific content to users, and promote the Museum at the same time. Next time I'm in London I'll give it a try.