Solar power has been investigated for some time by manufacturers; however, major issues such as space and durability have always been a roadblock.
The most interesting technique described by Apple, however, is the integration of the solar panels behind the actual LCD screen of a portable device. The solar panel would absorb ambient light that passes through the LCD screen of the device. This could eliminate any additional footprint typically required by the solar panels. If successfully implemented, Apple's iPhone, iPod and laptops, could require no outward changes in design to add solar power.