If you really, really, really want to prove you visited a highpoint, Ricoh has come out with the Ricoh Pro G3 GPS Camera which records your coordinates and elevation with your shot. It’s a little pricey for a 3.2 megapixel, 3x Optical Zoom Camera ($1,149 for the camera, gps card and software) but if you really want to prove something… You can use the software to come up with nifty maps with pop up photos from each location. Forum thread item.
The San Diego Tribune has an article on the phenomenon. It also notes that many people are using their own cameras and gps receivers and then synchonizing the EXIF and Waypoint data with free software tools including
Stuffware Photo Studio
Wideworld Media Exchange
Eyeballing the specs it strikes me that oziphototool is the easiest and simplest.
The article also notes that cameras and gps receivers are bluetooth wireless equipped could conceivably do this.
There are several programs that allow you to synchonize your GPS coordinated photos with maps.