I have so much fun geotagging my pictures and then, from Lightroom, placing the locations on the Google map. I use a Nikon GP-1 that attaches to my Nikon D3 (or D300). As we travel it is interesting to note our longitude and latitude as well as the altitude. Sometime at sea level it registers as a minus elevation!
The GP-1 also elicits much interest from other travelers, as they wonder what is that little unit on the camera accessory shoe? The unit can also be mounted on the camera strap with the included strap adapter mount. A cable from the unit connects to the camera through the 10 pin terminal. GPS data will be recorded when the GP-1 is able to detect three or more satellites. The data is recorded in the metadata of each photograph, and can be seen on the camera display immediately.
I wish I had had the unit for trips taken years ago so my map would be more complete!
No matter what kind of camera you have this is a great addition.
View My Travels in a larger map