Here's a very practical clip for filmmakers with interviews with bands, musicians and a film composer regarding how their music was used (in some cases for free) in a low budget award winning film, as well as what else went into the post-production workflow including editing and sound effects.
http://www.youtube.com/watch?v=ETsp60Pf3x0
http://www.youtube.com/watch?v=ETsp60Pf3x0