Free learning resources, like free software, is a matter of freedom, not price. It's about bringing the principles of free software to general knowledge and educational materials. Knowledge should be usable and accessible to all without restrictions and should not be treated as property. It is not an article of consumer goods that decays over time or wears out with use like a pair of shoes. Knowledge is a naturally abundant resource that improves with usage: the more it is used and passed around, the more it grows for the benefit of all. The introduction of measures designed to favor the ownership of knowledge, tailored to prevent people from accessing, using or sharing knowledge, is a conspiracy to inhibit human progress.

These principles on the freedom of knowledge have always been in the spirit of the GNU Project. In 1999, it formally introduced the concept of a Free Universal Encyclopedia and Learning Resource, which was fulfilled by the Wikipedia project.

Wikipedia

Written in collaboration by thousands of volunteers from all over the world, Wikipedia is nowadays the best example of knowledge made available to and usable by anyone without restrictions. Wikipedia readers are allowed to copy, use, and adapt the articles, provided that the source is mentioned and that eventual derivative works are released under the same terms (see Copyleft).

Project Gutenberg

This project offers general knowledge books that are free as in freedom. It publishes plain text digital versions of public-domain works. If you are looking for a copy of a classic book, your search should start here.

They have a very clear explanation about the difference between free as in price and free as in freedom related to printed material.

GNU Project

We maintain a list of free books mainly related to free software documentation, and we make GNU manuals available online. All books published by the Free Software Foundation are free as in freedom.

Free Technology Academy

The Free Technology Academy (FTA) is a joint initiative from several educational institutions in various countries. It aims to contribute to a society that permits all users to study, participate and build upon existing knowledge without restrictions. The FTA offers an online master level programme with course modules about free technologies. These courses are taught completely online in a virtual campus based on the Campus Project interoperability framework.

The FTA is a collaboration between the Free Knowledge Institute, the Open University of Catalonia (Spain) and the Open University of the Netherlands. A larger group of Associate Partners adds to the founding base with a network of organisations that share a common interest in offering courses in the area of free technology. The FTA is extending the current network of partners and collaborations continuously and encourages both individuals and organizations to contribute to the community.