Wikihood uses Google Maps to present you with information and selected images from Wikipedia relevant to any given location.
The application lets you see at a glance which Wikipedia articles are related to any chosen location. The displayed articles and images include information on people, culture, buildings, companies and organizations and geographical information.
As well as being available for the desktop Wikihood is available for the iPad and the iPhone. The mobile applications in particular are very useful for getting local information from Wikipedia when out and about.