Evan has just pointed me to this page on Wikitravel about their copyright policy:
http://www.wikitravel.org/article/Wikitravel:Why_Wikitravel_isn%27t_GFDL
I really think we can't afford to put this issue off any longer.
This follows on from my post back in August:
http://openguides.org/mail/openguides-dev/2003-August/000024.html