Mobile multiplayer online games list

Wanna know what games you and a group of people can play using your cellphones and location-based services?  Say, an urban treasure hunt is your style.  Or, perhaps, you want to play Undercover, a massively-multiplayer game that lets you work with other mobile users to save the world from evil.  On the list are also some handheld-based games as well as games that require the use of a digital camera,
like Square-Enix's Final Fantasy VII: Before Crisis.