Often you can locate the copyright owner from the copyright notice on the work. However, because copyright ownership sometimes passes through several hands since the work was first published a more detailed research may be required. In addition, some works (especially in the fine arts like film and music), can involve multiple owners --each with a separate right to different underlying works. Also different industries will require different methods for identifying copyright ownership.
For more details about finding copyright owners and getting the right kind of permission for your need visit Stanford's Copyrights & Fair Use Web site. The following Web sites can help you identify copyright owners and obtain permission to use their works.
Copyright Crash Course Permissions http://www.utsystem.edu/ogc/intellectualproperty/permissn.htm
Great site that lists all the major rights organizations for requesting permission.
WATCH (Writers, Artists and Their Copyright Holders) at the Harry Ransom Humanities Research Center - Univ. Texas Austin. http://tyler.hrc.utexas.edu/
A searchable database containing primarily the names and addresses of copyright holders or contact persons for authors and artists whose archives are housed, in whole or in part, in libraries and archives in North America and the United Kingdom.
Public Moving Image Archives and Research Centers - http://lcweb.loc.gov/film/filmofr.html
Copyright Clearance Center - http://www.copyright.com/