Answering one question myself. :-)
Am 29.04.2008 um 12:21 schrieb Johannes Beigel:
Does this page:
http://commons.wikimedia.org/wiki/MediaWiki:Commons_API
contain all the licenses that can occur for image files on Wikimedia
Commons?
I guess it's safer to use this category:
http://commons.wikimedia.org/wiki/Category:License_tags_attribution
as a referrence.
Johannes Beigel