With QlandkarteGT, you can also create tracks and routes for a Garmin GPS device.
The program can use downloaded maps and also the online OSM map.

Website project:
http://www.qlandkarte.org/

help:
http://sourceforge.net/apps/mediawiki/qlandkartegt/index.php?title=Help_for_QLandkarte_GT

And, creating a track
http://www.qlandkarte.org/screencasts/qlgt_plan_tour.htm

At first, the program wasn’t really intuitive, so I had some trouble to find out how to do all this.
To create a track in QlandkarteGT:
-In section ‘Map’ make sure OSM is on
-In section ‘Overlay’ click on distance polyline. Now you can create an polyline. This only creates straight lines.
-end polyline creation with right mouse button
-In the info-box, right click the and select ‘create Route’
-In the ‘Routes’ section, right click the new route and select ‘calc route’
-The route is calculated via the ways on the map
-Right click on the new route and select ‘make track’
Now you can choose to upload this track, or to save the .gpx file (file → export geo data) and put it on the Garmin device manually.

Good luck.