The Copyright Advisory Network offers four resources that will be of particular interest to librarians and teachers. The Fair Use Evaluator helps you make a fair use determination. Exceptions for Educators provides a step-by-step guide to determining if you can use copyrighted materials in your instruction under the educators exemption. The Section 108 Spinner is a tool for deciding if you, as a librarian, can make a reproduction of a copyrighted work. The Public Domain Slider offers a simple scale for determining if a work is copyrighted or if it is in the public domain.
I learned about the Copyright Advisory Network through The Tech Savvy Educator's post about the Public Domain Slider.
Applications for Education
The four tools offered by the Copyright Advisory Network will not take the place of teaching students the difference between legal and illegal use of copyrighted materials. That said, these tools could be useful aid in teaching how to determine if and how a copyrighted work can be used.
Here are some related items that may be of interest to you:
Classroom Copyright Chart
Copyright for Educators
The End to Copyright Confusion
Video Introduction to Understanding Fair Use