There are lots of places where you can download free, regularly-updated Garmin maps made from OpenStreetMap data. Here are three:
Map company Cloudmade
do the whole world. Go to http://downloads.cloudmade.com/
and browse for the region you're interested in. Let's say we're flying to Barbados on holiday: http://downloads.cloudmade.com/north_america/barbados
- download the IMG file and unzip it.
project has their own download page here: http://wiki.openstreetmap.org/wiki/OSM_Map_On_Garmin
. There are lots to choose from including different regions, levels of detail, and styling. Fill your boots, it's all free.My own
Garmin map, which is a routable UK & Eire with extra contour lines (thanks NASA!) updated weekly, is here: http://ravenfamily.org/andyg/maps
When you've downloaded your map, you should have one file with a .IMG extension.