Just found this website this morning while searching for information about the copyright of various quotations etc from a number of different people. Thought it might be helpful to others.
http://tyler.hrc.utexas.edu//
Called WATCH (Writers, Artists and Their Copyright Holders), it is jointly run by the University of Texas in the USA and The University of Reading in the UK, and has details about copyright law etc in both countries. There is also a very simple search facility - you enter the first name and surname of the writer/artist that you're looking for and it tells you who holds the copyright to their work. It didn't have answers for quite all of my queries, but it certainly cut down the search time considerably!
Snowcat