RouteYou offers the option to download your Garmin tracks
direclty from the RouteYou website to you Garmin GPS without
the intermediate step using MapSource.
Connect your Garmin GPS to your PC (you must
have received a cable with it)
Select next to the blue triangle 'Transfer direcly to my device'
(the first time, you might have to install once an extra software of
Garmin). The track will be uploaded to your device. Hit the road!