Apple's interest in solar cell technology for its products has been evident for many years based on patent applications covering the technology. A report from several months ago indicated that Apple has indeed been holding discussions about solar technology with several Taiwanese vendors, although any such projects would still be in the research stage and not yet near a public release.
Drawing from Apple's new patent showing iPod with integrated solar cells
Coincidentally, Patently Apple reports that Apple was just today awarded a patent for a power management system that would enable the company to place solar cells on the exterior of devices such as iPods and integrate that power source with an internal battery. The patent was filed for in mid-2008 and was first revealed in early 2010 as the patent application was released to the public.