AppleInsider claims that Snow Leopard will include developer hooks that will determine a Mac's geographical location and provide additional multi-touch support for Mac laptops with glass trackpads.
While Macs don't typically come with GPS built-in, the location determination feature will work similarly to the original iPhone and iPod touch: Using triangulation between several known WiFi locations, a technique introduced by a company called Skyhook. There are tools you can purchase to take advantage of Skyhook positioning today, but Snow Leopard will give developers the option of including them in any application.
Similarly, Cory mentioned some time ago that betas of Firefox 3 already take advantage of multi-touch gestures. AppleInsider's source claims the framework has been planned for inclusion since June.
The two sets of developer hooks will bring Mac OS X closer to its sibling platform, the iPhone. MacDailyNews claims it's a union that will produce a "MacBook touch," for which prototypes they claim exist today.