Guidelines
With new digital storytelling technologies available in the classroom every day, much of what is considered copyright laws are really copyright guidelines. Here is Hall Davidson's chart of copyright guidelines. Again, many of these guidelines are yet untested in the law.

Educational Use
Teachers have much leeway in terms of educational projects beginning and ending in the classroom. Students can use nearly any image they find online or even portions of copyrighted songs for educational projects that are presented in class. However, as soon as additional copies of that project are made or the project is placed online, clear laws are broken.

Royalty Free Images
Rather than searching for images through google, know that many images exist on the internet that someone has already given permission for you to use though they sometimes ask that you give them credit for their work.

Royalty Free Image Sites:

Pics4Learning <I start here
most organized and child-safe, but smallest selection of images
these are free to use without attribution to the original author

MorgueFile.com <then go here
large collection of professional images, also free to use without attribution
these are not necessarily organized or child-friendly

Flickr - Creative Commons <finally here
choose a category and click on "see more" to search
this is the largest collection of generally amateur images
most of these require that you give credit to the author to use,
keep track of the author's names

Royalty Free Music Sites:

Alan Levine has a terrific list of these.

Also Pod Safe Audio

or create your own with Garageband

Other copyright resources:

Articles

Education World's Five Part Article on Copyright for Educators

Podcasts

A good time can be had and much can be learned by listening to Barely Legal Radio, available via podcast about entertainment law. Much applies to the classroom.

Marco Torres's podcast on respecting copyright