There is a very creative finnish startup company named: SVS Innovations Ltd who are developing innovative technologies. they've developed a 3D engine (Capsule 3d Engine) or a 3D viewer.

Johannes Kuhlmann (aka jfk) shows off a 3D tracking system on N900 using OpenGL ES 2.0.

this idea was mentioned by Johnny Lee and was used in a game for Nintendo DSi.

"This video shows a 3D effect that was first publicized by Johnny Lee who used a Wiimote. It is achieved by tracking the user's head and adjusting the camera through which the scene is viewed accordingly. The device's screen appears to be a window into a virtual world."