I found this gem a few months ago, and I was impressed immediately.

Directly inside the Finder, this shows if a photo has GPS data inside the EXIF record, displays that coordinate, and even "flies" your Google Earth to that location! This is a huge help if dealing with geotagged photo files.

A super cool bonus is the support for URLs that contain GPS coordiantes, for services such as Flickr. Although I don't use Flickr, I do love to use Panoramio and WikiMapia, and the direct link with GPS-Info is incredibly helpful for me. With some fiddling, you can even add your own services to that list!

One feature I would love to see is a KMZ export including a thumbnail of the photo, and eventually the export of more than one file at once into one KMZ...

But hey, it is free, and the devleoper quickly responded to my suggestions...