The next major version of Apple’s Mac OS X, version 10.6 “Snow Leopard” will offer the ability for developers to use location-aware features found in 3G iPhones as well as expand the amount of software with multi-touch features.
One of the biggest additions will be location-aware software. Whether this means Apple will add GPS hardware or will stick with using the existing network hardware to emulate their position is unknown. As Apple Insider points out, the original iPhones use the network hardware feature to come up with a fairly accurate location (although not nearly as close as dedicated GPS hardware).
They’ll also be able to use some of the multi-touch functionality from the MacBook/MacBook Pro touchpads. This should expand the range of software using multi-touch gestures from standard Apple applications like iPhoto and Safari, to virtually any application that could make use of it.
Ideally that would involve touchscreen displays (perhaps an Apple Tablet?) at some point in the future, since it would be easy to do, given that OS X for Macs and OS X for iPhones share some code.
Read: Apple Insider