Education should be free for everyone.
Meaning, open source content that’s shared over technology leads to differentiated instruction, tools for all grades and all levels of ability within each grade. Example: http://www.freereading.org/ & Kids’ Open Dictionary: http://www.dictionary.k12opened.com
This is about assembling classroom materials on a class-by-class basis, and adding them to the great library of materials that anyone can use.
Things that are free now but are not open, may not always be so. Things that are open and free are likely to remain free and open.
CreativeCommons license: recommended license for education: CC BY or CC SA… Basic categories: Attribution (BY) Non-Commercial (NC), No derivatives (ND) Copyleft-Share Alike (SA)
GFDL – Share alike license used by Wikipedia and others. Public domain, not copyrighted, you can use however you like. Many custom licenses (e.g., morguefile and STock.XCHANG)
The Creative Commons License requires you to include a credit for the material — text, music, audio, images — almost always. This should include the name of the real person (or user name and site) that created the source, and ideally a URL as well. GNU/GFDL license of wikipedia materials operates a little differently, but amounts to the same credit requirement.
Flickr is the largest collection of creative commons images on the web. You’re not required to leave a comment to the person you borrow the photo from, but they love knowing the stuff is being used. Please make sure you leave a comment, as well as giving credit to the user (my content is mostly Creative Commons, and available here).
Recognize that a photo with people in it needs model releases from the people in the image. Just because an image is Creative Commons doesn’t mean that the photographer actually got model releases for all the people in the photo. So be cautious when using them.
Music & Sound Effects
As far as music and sound effects, there are a number of sources. www.ccmixter.com is sort of free, but be careful. Read the site licenses carefully, and be aware that schools in particular can get slammed by contest rules, and other trip-ups. Museopen.org is primarily classical and acoustic. The Freesound Project is sound effects of nearly every type imaginable. You must be logged in to be download.
Not much video yet, but will find the links later.
MP3 and .wav are the primary files for audio, but also .ogg MP3 is a proprietary format, but .ogg is open-source, and opensource radicals tend to prefer this type. Video programs are often loaded with spyware to search for copyrighted materials, and there are also way too many video formats.