What is Open Access?
Open Access is not the same as OER. Open Access materials are still under traditional copyright. They cannot be copied, shared, or remixed. The thing that makes them distinctive is that, unlike traditional journal articles, you can read them on the web without having a subscription or paying for a download. This is important for the free flow of scholarly communication and the sustainability of libraries; however it doesn't allow you to embed the content in your course. You can still only link to Open Access articles, not copy or share them.
Open Access articles are articles that are free to the reader (and the library.) They are found:
"What is Open Access?" by Sarah Morehouse is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License.
Flickr - After searching by keyword in Flickr, click on Any License and select the usage license of your choice.
YouTube - After searching by keyword in YouTube, use the Filters feature to filter your results to those videos with a Creative Commons License.