cK-12 http://ck12.org/flexr/
Flatworld Knowledge http://www.flatworldknowledge.com/
Merlot http://www.merlot.org/merlot/index.htm
Connexions http://cnx.org/
Wikibooks http://en.wikibooks.org/wiki/Main_Page
OER Commons http://www.oercommons.org/
Open book Project http://openbookproject.net/
Community College Consortium for Open Educational Resources http://oerconsortium.org/discipline-specific/
Orange Grove Texts Plus http://www.theorangegrove.org/OGTtest.htm
Curriki http://www.curriki.org/xwiki/bin/view/Main/WebHome
Open Culture: http://www.openculture.com/free_textbooks
Textbook Revolution: http://www.textbookrevolution.org/index.php/Main_Page
MIT OpenCourseware: http://ocw.mit.edu/
Scribed: http://www.scribd.com/
Bookboon: http://bookboon.com/
Boundless ($19.99): https://www.boundless.com/
College Open Textbook Collaborative: http://www.collegeopentextbooks.org/
Open Stax College: http://openstaxcollege.org/
LearningPod http://www.learningpod.com/
Open Education Group: http://openedgroup.org/
Saylor Books: http://www.saylor.org/books/
U. Monnesota Open Academics: https://open.umn.edu/opentextbooks/
SUNY Open Textbook Initiative: http://opensuny.org/omp/index.php/SUNYOpenTextbooks
DT - Digital Textbooks blog - http://digital-textbooks.blogspot.com/
Open Access Textbooks (McKiernan) - http://instr.iastate.libguides.com/oats
MOOCs and Libraries (McKiernan) - http://moocsandlibraries.blogspot.com/
Academic Earth http://academicearth.org/
Open Courseware Consortium http://www.ocwconsortium.org/
FolkSemantic http://www.folksemantic.com/
SOFIA http://sofia.fhda.edu/gallery/
Orangeware http://www.theorangegrove.org/OGMain.asp
Curriki http://www.curriki.org/xwiki/bin/view/Main/WebHome
Open Culture Free Courses http://www.openculture.com/freeonlinecourses
HippoCampus http://www.hippocampus.org/
Wisconsin ide@s http://www.ideas.wisconsin.edu/
Khan Academy http://www.khanacademy.org/
VIDEOtalks http://videotalks.org/
Einztein http://www.einztein.com/
Open Course Library: http://www.opencourselibrary.org/
Class Central: http://www.class-central.com/
Free Video Lectures: http://freevideolectures.com/
Online Courses Directory: http://www.onlinecourses.com/
Mooctivity: http://www.mooctivity.com/
Open Educational Resources for California http://grou.ps/oercenter
Open Learning Initiative (carnegie Mellon) http://oli.web.cmu.edu/openlearning/index.php
iCommons http://icommons.org/
University of Oxford Podcasts: http://podcasts.ox.ac.uk/
Coursera: https://www.coursera.org/
My Education Path (online courses directory): http://myeducationpath.com/courses/
Class Central: http://www.class-central.com/
David Archer Global Warming: http://forecast.uchicago.edu/lectures.html
CourseTalk: http://coursetalk.org/
CourseWorld: http://www.courseworld.org/
Free Book Notes: http://www.freebooknotes.com/
CliffsNotes: http://www.cliffsnotes.com/
SparkNotes: http://www.sparknotes.com/
Schmoop: http://www.shmoop.com/
GradeSaver: http://www.gradesaver.com/
Textbook Madness: http://textbookmadness.com/
Get Textbooks: http://www.gettextbooks.com/
Chegg: http://www.chegg.com/
Free Books: Top 20 Web Sites: http://websearch.about.com/od/dailywebsearchtips/qt/dnt0607.htm?nl=1
Class Central: http://www.class-central.com/
MOOC List: http://www.mooc-list.com/
Online Courses: http://www.onlinecourses.com/
CourseBuffet: https://www.coursebuffet.com/