Looking for GPS software/help for my hobby?

My hobby is metal detecting and I am looking for some mapping/plotting software that will let me input coordinates from a hand help GPS reciever and plot them on a map. Then I would like to be able to go back to these locations using the mapping. Keep in mind that I know absolutely nothing about GPS. Whan I find things with my detector I would like to “mark” the location. Is this a “waypoint”? Then I can go back to these locations for further study. I figure I can plot civil war troop movements this way and find more artifacts. I would also like to use it to mark out a search grid to make sure I am covering the area. I would also like to have the software on my laptop and a USB reciever. Is this what GPS is for/can do for me? If you could suggest an online tutorial also, that would be great. Am I going in the right direction with this?

I ran across this today

http://www.maps-gps-info.com/fgpfw.html

Metal Detecting April 11, 2010