WhatSong is a site that provides information on iconic songs that over the years played in films and tv shows. It's not fully complete, but anyone with a WhatSong account can add in titles that aren't already there, though they can only submit songs submitted to titles that they themselves submitted. This should be changed sometime so that anyone is able to submit songs to any title, which can certainly help those title submitters that were unsure of what songs were featured in titles they themselves submitted.