At the BIRTV show we spoke to Ikan, the American distributor of the Chinese made PD Movie wireless follow focus system. They gave us a rundown of a number of products from the company, including the Remote Live, Remote Air Pro for iPhones, and the Remote Air 2, a more traditional wireless follow focus handset.
It is certainly a neat idea to use an iPhone to control focus, but perhaps the most useful aspect of the PD Air system is that the motors have their own batteries inside. This is potentially great for use on smaller brushless gimbals, Steadicams and lightweight rigs where an external power source would add unwanted bulk and cabling. This is in contrast to almost every other system out there that need external power.
For more details keep an eye in the Ikan website.