Navigation software to connect your Mac with most GPS receivers. US and Canada MacTopos map DVDs, digital marine charts, MacElevation display, accessories, and great service.
GPSy -- Macintosh GPS Communications. GPSy is the only Macintosh GPS program compatible with
any NMEA-0183 compatible GPS/Loran-C/DECCA or other navigational system.
Chimoosoft's GPS Connect for Mac OS X is a freeware program which connects to Garmin GPS receivers and allows upload and download of waypoints. NMEA Protocol is also supported for other brands of GPS receivers.
GPSBabel converts waypoints, tracks, and routes between popular GPS receivers and mapping programs. It also has powerful manipulation tools for such data.
RouteBuddy is a GPS enabled mapping application for OS X. All the essential functions of your GPS device are supported; all you need is a mac, a Garmin GPS, and of course RouteBuddy.