For more information or to download GPSphotolinker for the Mac to to
http://oregonstate.edu/~earlyj/gpsphotolinker/

Please note that the GPS Photo Linker software for the Mac is not compatible with OSX 10.5 Leopard yet, I'm sure it will be someday soon, but not yet.

The Garmin eTrex Legend HCx

Geotagging group on flickr

A few things you'll want to look for when shopping for a GPS unit to use for geotagging your images:

1. USB interface. Believe it or not many Garmin units still use DB9 (Com Port) connections.
2. Make sure the unit save track data ... not all of them do. I have a very nice nuvi 250 in my truck but it does not save tracks.

Here are some Windows programs that do what GPSPhotoLinker does (I have not tried these programs)

PixGPS

RoboGEO

Various GPS apps at ZDnet