You can use a paid service like the Copyright Clearance Center and in many cases get an instant price for your proposed use. If the work is not in their database, they will attempt to locate the copyright holder.
Otherwise, you may request permission yourself. See the Sample Letter below.
Finding the copyright owner can be challenging. The following links provide additional information.
You should consult the location on the work or packaging containing the copyright notice (such as the copyright page in a book, or a link to a “copyright / legal” page on a website), as well as any acknowledgments. If you have a photocopy or other reproduction that does not contain a notice of copyright or acknowledgments, consult an original copy of the work.
Most works contain a copyright notice, but because copyright ownership can be transferred after publication, your copy may not identify the current copyright owner. Works published after March 1, 1989, are not required to carry a copyright notice in order to be protected under the law. Therefore, the absence of a copyright notice does not mean that the work in question may be freely copied.
If the work does not contain a copyright notice, the notice is no longer accurate, or you are unable to locate the person or entity identified in the notice, the first step in determining ownership is to contact the publisher of the work that you wish to copy. In most cases the publisher will either control the rights or be able to refer you to the current owner. For unpublished works, permission to copy must be obtained from the author of the work. If these steps prove unsuccessful, you should contact the U.S. Copyright Office. The U.S. Copyright Office maintains records of registered works by author and title, some of which may be searched online at www.copyright.gov/records/. For more information, ask the Copyright Office to send you Circular 22, “How to Investigate the Copyright Status of a Work,” by phoning (202) 707-9100, or going to www.loc.gov/copyright/circs.
Oftentimes a work contains a variety of copyrighted items that are used by permission of another copyright owner. In most of these instances, the copyright owner of the entire work has obtained only nonexclusive permission to use these items. You should check the credits and acknowledgments in the work to identify the rightful owners of these copyrighted items and contact them for permission.
If you don’t receive a response to your request for permission, you cannot assume that you have been granted the necessary permission.
National Association of College Stores. Q&A Concerning Copying Print and Digital Works (http://www.nacs.org/toolsresources/cmip/copyright/questions/copying.aspx)