In the thread re: Music Rights, I mentioned an article from the winter '05 edition of "Filmmaker - the Magazine of Independent Film" regarding issues of rights procurement. The article was titled "Untold Stories."
The article and additional information is availible from a web site:
The article in Filmmaker was culled from the report "Untold Stories" and is linked at that same site along with some useful discussion on the subject and the subject of "Clearance Culture" the term for the latest sentiment on rights and clearances.
It's good reading and might clear up many questions on the subject.