i3D, the app we posted about last month that showing a concept of glasses free 3D using Head-Coupled Perspective on the iPhone 4 and iPad 2. Well the app used for the demo video is now available in the App Store. There has been a huge interest in the technology with over 1.5 million views of the videos to date!

The app known as i3D, tracks the face of the user in real time. This information tells the app how the user is looking at the display and updates the perspective of the 3D scene giving the user the illusion that he is looking at a small window.

The app is available for free and will work with the iPad 2, iPhone 4 and 4th generation iPod touch. If you want a refresh on how well this works, take a look at the video after the break. If you download the app, let us know what your think in the comments!

[Free - iTunes Link]