Saw this interesting product at Computex 2008: PhotoTrack
This is a GPS device that stores location information. You just carry it with when you travel and then use the software which add the location information to your photos. It does this based on time syncronisation.
It works with Flickr and works with all digital cameras.
It also has a mapping software that maps out your trip.
Excellent product, too bad the software is Windows only.
At some point of time, camera manufacturers will add a GPS device within the camera, until then use PhotoTrack
More information: www.wonderproud.com