United States copyright laws permit the Fair Use of copyrighted materials without the need to seek expressed permission from the copyright holder. Since what is considered “Fair Use” is determined on a case by case basis, the user may wish to obtain written permission from the rights holder to remove ambiguity. Documentation of the process should be maintained.
Excellent resources on obtaining permission to use copyrighted works are readily available. This Best Practices Guide may be a helpful place to begin. To obtain permission to use excerpts from books, periodicals, music, photographs and motion pictures, the links below will be useful. You may also contact the author and/or owner directly, although it's important to realize that the author may not be the copyright owner.
For books or periodicals, contact the Copyright Clearance Center.
For music, contact the record label, which is usually represented by the Recording Industry Association of America or Broadcast Music Inc. or American Society of Composers, Authors, and Publishers.
For motion pictures and videos, contact the Motion Picture Licensing Corporation, which is authorized by most major Hollywood motion picture studios to grant licenses to nonprofit groups, government organizations and businesses.
If you would prefer to contact the author and/or owner (e.g. publisher) directly, some tips and sample letters can be found at the following sites: