Open educational resources (OERs) are freely available for sharing and/or adaptation and have been defined as “teaching, learning, and research resources that reside in the public domain or have been released under an intellectual property license that permits their free use or re-purposing by others.” (Atkins, Brown, and Hammond, 2007, p. 4).
OER types include:
The OER resource movement has received additional attention with the recent focus on student retention categories of accessibility and educational costs. OER's represent educators recognizing and attempting to meet the need for openly shared resources that are freely available for others to use.
Here are some institutioin-specific resources focused primarily at the university/higher education level for your perusal. Goldberg and LaMagna.
Many of the sites allow users to create a free account and to search for and save OERs as well as to create new OERs and share them with others.