While looking into implementations of PhysX, we spoke to Nvidia this week and discovered that Apple's iPhone fully supports PhysX.
While PhysX on Nvidia's own hardware is available only on GeForce 8 series GPUs and up, PhysX technicaly is able to work without an Nvidia GPU, provided that the necessary work is done of course, and the proper licenses are in place. For example, PhysX works on the PlayStation 3 using the the CPU and the SPU, which are both part of the Cell processor.
According to Nvidia: "PhysX is available on the iPhone--running on the ARM processor core. This versatility is what is driving PhysX adoption across multiple platforms including consoles and PCs," Nvidia told Tom's Hardware.
At the present time however, no official announcements have been made. While there are really neat 3D games on the iPhone, there are none out there that take advantage of PhysX. As far as we're aware, Apple does not have any publicly available documentation for PhysX development.