You can search copyright information through the Library of Congress’ site that searches for works registered and documents recorded by the U.S. Copyright Office since Jan. 1,978. See http://www.copyright.gov/search/
A large portion of your copyright permissions, particularly for print materials, can be secured through the Copyright Clearance Center (CCC), the largest licenser of photocopy reproduction rights in the world. Click on “get permission” and follow the instructions. You will need to know the full bibliographic information for the item, plus the term of your class and an estimate of the number of students you expect. Please be aware that there is a fee for this service.
If permission cannot be secured through CCC, you need permission from the owner(s) of the copyright. This could be the author(s), the publisher, a third party, or a combination of the above. It can take time to track down the source of ownership. An additional challenge is the short duration of each quarter.
Note: A response does not guarantee permission. You may be given permission, denied permission, or referred to another source.
Copyright Clearance Center: 1-2 days
Commercial publisher: 8-12 weeks
Unusual source: 16-20 weeks