A key use of a cell phone is to contact emergency services while on the road.
However, many people in the act of travelling are not able to coherently relay their location to 911 dispatchers. A cell phone with a built in GPS reciever, however, could send the phone and caller's location to a dispatcher automatically. The Garmin Navtalk already does this.

According to the news blurb I saw this on, this technology will become a requirement in a few years.

I saw this coming when Bill Clinton ordered Selective Availability removed. Humorously enough the idea was also portrayed in the Charlies Angels movie (although to the fakest degree). Some guy in Citrix class even mentioned it a year ago.

There is some opposition.... Certain safegaurds will have to be taken to make sure the GPS information can't be exploited. For example: An unchecked wireless provider could monitor everywhere you shop the day after Thanksgiving and sell the information to JC Penney.
The combination of hundreds of cell phone makers, thousands of wireless providers, and the fact that pretty much everyone and they're kids have a cell phone will make this a fairly hefty job.