Here you will find resources on how to build you own enclosure for your router to make using EWRT practical.

Check out the following sites:

http://www.2xlc.de/outdoor_wrt.html

http://www.mervin.net.au/wireless/template/waterproofEnclosures.php

http://futonmonkey.wordpress.com/2010/06/04/outdoor-linksys-wrt54g-tm-router-build-2-0-3/

If you know of any similar resources please leave a comment below.