I've written a feature (applied to HEAD) that enables administrators to add a license selection box to Special:Upload, they have to write a MediaWiki:Licenses message with information which will be used to construct the form, a sample message would look like:
* Free licenses ** GNU Licenses *** GFDL|GNU Free Documentation License *** GPL|GNU General Public License ** Creative Commons licenses *** ....
The bullets that have the form "Template|Text" are selectable templates, if they're selected {{Template}} will be added to the file page under a == License == subheading, the bullets that have the form "Text" are selecteble but have no effect, both can be localized through the MediaWiki namespace, for instance one could add "Frjálsa GNU handbókarleyfið" to MediaWiki:GNU Free Documentation License and "Frjáls leyfi" to MediaWiki:Free licenses to translate the corrisponding items into Icelandic.