Great!
I'll let someone else describe the steps they download for an e-trex. I don't have any Garmins.
To save directly onto the computer though, there are two ways of doing it.
For an individual waymark, there .kml, .loc, and .gpx links under the waymark photo.
For bulk waymarks, when you are in the Search Results Page there is a check box on the left of the waymark. Click the waymarks you want and at the bottom of the page there are links for the .kml, .loc, and .gpx formats. Also at the bottom is a "Check All" box if you are interested in all of them.
Presumably you save the files to you computer and then upload them to the GPS - at least that is what I would do.