Inclusion in this list does not imply endorsement.

ACADEMIC EARTH

Lots of high-quality lectures; all from American universities.

CONNEXIONS 

Uses principle of learning objects (small modules); expert groups can create "lenses" which group a collection of approved/vetted objects.

EDUFIRE 

"Dating service" for individual and small group tutoring for standardized tests and foreign languages. Small fees.

FLAT WORLD KNOWLEDGE

Open college textbooks; just ramping up. 

INSTRUCTABLES

MAKE

MERLOT

"Peer-reviewed online teaching and learning materials." Includes options for contacting colleagues and disciplinary experts.

OER COMMONS 

This database site provides searchable access to numerous OER content providers, including MIT OpenCourseWare

OER PROJECTS 

Wiki with comprehensive links to OER projects.

OPEN CULTURE 

Highlights some of the best and most intriguing open resources on the web, with lots of search options.

OPEN HIGH SCHOOL OF UTAH

Online public charter school opening fall of 2009, based on open educational resources.

OPEN LEARN  

Materials from and access to The Open University, UK, one of the world's open education vanguards. 

OWL INSTITUTE 

Based in Duluth, supporting homeschoolers and more.

PEER2PEER UNIVERSITY 

"The Peer 2 Peer University is an online community of open study groups for short university-level courses....There is a huge amount of Open Education Resources 'out there'... However, it is very difficult for a self-learner to just sit down and learn from these resources in a sustained fashion." 

TED TALKS

20-minute presentations about innovation and creativity by a wide range of experts.