ok, first of, media like music and pictures/textures is not software code, an thus cannot be GPL.
that is why i think we/you shood use the CC liense. http://creativecommons.org/
http://creativecommons.org/licenses/by-sa/3.0/
this is a good licens if you ask me, this is not the howle license but a summery..
this is the license http://creativecommons.org/licenses/by-sa/3.0/legalcode
Btw hi again!