Apple and the music industry are engaged in a new marketing initiative - collectible iTunes cards.

Introduced at the South by Southwest Music Conference and Festival iun Texas this week, the iTunes Custom Cards are prepaid, numbered limited edition cards featuring original artwork and codes to download music form more than 200 specified artists at this point.

In essence, the cards mean a band can give away or sell a card that relates to the act that entitles the recipient to download music by that artist through iTunes.

Gorillaz distributed a limited-edition iTunes card to attendees of its Dirty Harry single launch party at the show.