Wikitude, augmented reality Wikipedia, is in the AppStore

Wikitude is an augmented reality application which uses Wikipedias content to add a layer of information to the world around you. Using the camera on your smart phone, or in this case an iPhone you can point your phone atsomething and wikitude will serve up any wikipedia infor that is available.

Also interesting is that Wikitude - in addition to using the content from Wikipedia - gets local reviews from London-based Qype, and crowd sourced information from its Wikitude.me website. As are result, you can write your own notes and eventually share them with other users...

Enough said. If you own the iPhone 3GS, this is one of those must have apps.