telkoth

I'd like to play some music before and after a weekly live shoutcast I do. would the remixes I find here (and elsewhere) legally safe for such use? I'd of course give the names/artists of the songs after/before they play... I more worry about the legality of remixes in general, ex: is a remix of the Zelda theme a derivative work owned by Nintendo, and therefore Nintendo's permission is needed for my use?