or just use the openstreet maps for Europe. They are generally very good and if you want to do something specific like MTB they can be very good depending on where you are.
There is a bunch of links to various sources of maps here http://wiki.openstreetmap.org/wiki/OSM_Map_On_Garmin/Download
I’ve just put some from ‘Team ODI’ in a couple of minutes ago and they look good. I’ve used Lambertus’ maps before as well and the openmtbmap.org stuff is great as long as there is good data for the area that you are in.
Just fire the maps up in mapsource first to make sure they are good in the area that you are visiting but I haven’t had many problems so far