You can't (currently) download a country but you can batch-download a specific area. ModRana can do it on its own but it is generally better to use third-party solutions for that since in the former case the CPU usage gets quite high for some reason and the device can get a) unresponsive to the point it appears locked up and fool the user to rebooting it; and b) hot.

See also http://talk.maemo.org/showthread.php...54#post1330454.