The Rosetta Project is a website which has a large library of illustrated children’s books composed of works in the public domain. There’s no doubt that you have probably heard of many of each which are posted on the website, including: Old Mother Hubbard, Mother Goose Rhymes, Robinson Crusoe, The Ugly Duckling, and The Three Little Pigs. Many other books are also located on the Rosetta Project’s website.
I’m sure the Rosetta Project was inspired by the Gutenburg Project which is an archive of public domain literature in text form. On the Gutenburg website, you can search for Shakespeare, download all of Mark Twain’s various works, get the Time Machine by H. G. Wells (or download the audio version), or browse the recently added music section (another related site is "the Classical Music Archives").
All of the above is thanks to something called "the Public Domain", which is being artificially slowed down due to various laws. Lots of websites have stories about the semi-recent happenings, such as Salon, Wired, and the New York Times. If you would like to read more about the Bono Copyright Extension and its impacts on our culture, check out "Opposing Copyright Extension" or browse around Lawrence Lessig’s web page.
If you’re interested in placing your work in the public domain or loosening the restrictions on what can be done with things you produce, check out Creative Commons.
The public domain is a great thing. It allows people to see and hear things that they would not otherwise be able to experience, provides a great resource to draw from for derivative works, and can also be utilized as an archive of the works of the past.