Awhile back I posted that I was going to figure out how well the Sony GPS-CS1K works with Mac computers. After working with the GPS unit for awhile, I'm happy to say the answer is "really well."
There are several freely available software programs you'll need in order to get the job done, but they're just as easy to use as Sony's official software for the PC.
GPSPhotoLinker - This program is the best I found for writing Geo tags to the EXIF data of my photos. It's as simple as selecting, and clicking a button. You can determine whether you want to use point before, point after, or average. This is necessary because the GPS unit doesn't necessarily capture GPS data at the exact moment you take your picture, so it has to make a software guess.
HoudahGPS - This program will help you convert the Sony GPS .log files to other formats for use in a wide range of tools. This is useful if you want to upload your GPS points to Google Earth, Google Maps and other websites or utilities.
Basically those two software programs are all you'll need to get started.