Tobii has now released a new extensive white paper describing how eye tracking can be used to complete user tests on mobile devices. There are several challenges when using an eye tracker together with a mobile phone, both in the physical setup and in the human physiology. The paper explains the challenges and presents three different setups that works.
You can read and download the white paper Using eye tracking to test mobile devices on Scribd here
Recently another video clip was released on YouTube by Herbstwerbung showing how a Tobii x120 eye tracker was used to track the eye movements when using an iPhone. Watch the clip below: