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Books for free can be used for students who have difficulty reading or for students with vision impairments. Once I had a student with a concussion and he couldn't read during our silent reading time. Having an audio book would have been a wonderful solution. Books can be downloaded to ipods or MP3 players. Have students misplaced some of your novels? Do you need multiple copies of a book? Who has money in their budget for more books? Well here is your solution. This site would eliminate the problem because you could download multiple copies of the book or you could download and make CD's. I would use this site to download copies of Swiss Family Robinson to use with a lesson about Human Environment Interaction.
Who needs textbooks when there are flexbooks? As education funds are getting slashed, teachers could quite possibly use flexbooks. They don't cost a penny, and it is an alternative to having programs and teachers slashed.
Free images that meet creative commons license. Students are always looking for images that they can use for projects. As with the flickr site, students could use these images for a variety of projects.
I am still investigating this site, but seems to be valid for royalty free music and meets the terms of creative commons licensing. I could see students using clips of this music in videos that my students create.