Maybe you haven't noticed, but right now, all of Apple's Mac computers ship with either Intel integrated graphics or AMD discrete GPUs by default. According to SemiAccurate, that's about to change. The site quotes unnamed sources as saying Nvidia "has won the next round of Macs," and that GeForces could start showing up in next year's models featuring Intel Ivy Bridge CPUs.
SemiAccurate says this change of heart has to do with Apple's purported decision to cancel a MacBook Air model featuring AMD's A-series APU. Reportedly, that system was "really close to production" this spring, but Apple balked because of the supply problems plaguing AMD's 32-nm products. The current, Intel-powered MacBook Air was Apple's "plan B," SemiAccurate claims.
The link between those two rumors might seem tenuous, but Apple does have a reputation for being tough with suppliers. Nvidia GPUs were unceremoniously phased out from the Mac family after Nvidia's solder bump problems, which caused chip failures in many pre-built machines, came to light.
In any case, Apple adopting GeForces again would be great news for Nvidia—especially considering Mac sales are still growing much faster than PC sales. Nvidia has stopped developing integrated graphics chipsets, though, so a chunk of Apple's Mac lineup may feature Intel IGPs regardless.