General
- OER Commons
- OER Recommender
- Wikibooks
- OpenCourse.org
- Textbook Revolution
- National Science Digital Library (NSDL)
K-12
- Curriki
- Free High School Science Texts
- Schools Without Limits
- California Open Source Textbook project
- CK12
- K12 Online (Wikia)
- K12EdCom
- Wikieducator K-12 math page
- MoodleCommons.org
- Yahoo Teachers
- Next Vista for Learning
- FreeReading (early literacy)
- Open Educator Inc.
- Wikispaces
- Hippocampus/NROC
- Phet (science simulations)