The Technology, Education and Copyright Harmonization Act (TEACH Act), which passed in 2002, addresses the use of copyrighted materials in distance education courses. Basically, it amends U.S. Code Title 17 (U.S. Copyright Law), sections 110(2) and 112. However, in order to utilize the TEACH Act, certain requirements must be met in advance, including having a copyright policy at your institution.
Use the TEACH Act as a checklist that must be met in order to utilize a work in your class. Remember, however, that the exemptions provided in the TEACH Act are "limited in scope" (Russell 46). You can always use fair use as well.