It seems that there are lots of free software applications around that are capable of capturing the data from a GPS unit. One that looks like it might be a good one for you, is Geotag, which uses GPS data to store location information within images. If this is a bit too much, and you just want to limit it to measuring distances, try The OpenGPS Tracking System, which works in conjunction with GoogleMaps to let you plot on there.
I know there are simpler GPS softwares, but unless you have some facility to work out the distances between two GPS location co-ordinates, you probably don't want to go that basic. The two listed above are free, by the way.
I know there are simpler GPS softwares, but unless you have some facility to work out the distances between two GPS location co-ordinates, you probably don't want to go that basic. The two listed above are free, by the way.