The Center for Social Media has put together a "Code of Best Practices in Fair Use" that aims to "clarif[y] the fair use of copyrighted materials for teaching and learning, putting an end to copyright confusion for educators."
Temple's David Post:
"There's something of a 'political' slant to this, it should be noted. The document is, explicitly, trying to arm educators so that they will assert their fair use privileges, more vigorously than they have done in the past, all as part of a campaign to re-invigorate the doctrine. ... Worth a look, if you've ever found yourself concerned about using copyrighted material in your teaching or writing."