Preview in Leopard includes GPS support
Looks like the props to NASA in the About for Preview 4 is all about the GPS support. Images can now get stamped with coordinates where they were taken and Preview makes use of that to display a map of where the image was shot.
From the Leopard 300 new features page under Preview:
GPS Metadata Support
Get real information from your photos. If your image has embedded GPS metadata, Preview will show you exactly where that perfect photo was taken. Open the Image inspector and select GPS. Preview pinpoints the location where you took the photo on a world map. From there you can even open the GPS location in Google Maps.