A few points:
- What subject are you looking at? The answer varies significantly if you are not looking at science/math/engineering.
- Define 'graduate level' because the Khan Academy (Not Kahn) is far from graduate level.
- This is a very good link. I'll paste an excerpt here:
MIT OpenCourseWare : undergraduate and graduate subjects taught at MIT.
Open Yale Courses : astronomy, biomedical engineering, history, economics, English, philosophy, physics, political science, and psychology.
UC Berkeley Webcast : biology, computer science, electrical engineering, physics, political science, and psychology.
Stanford Engineering Everywhere
NPTEL basic undergraduate science and engineering courses. The courses include biotechnology, civil engineering, computer science, electrical engineering, electronics and communication, and mechanical engineering.
McGill Univ. COurses OnLine (COOL) : chemistry, biology and computer science.
UCLA BruinCast offers some free audio/video lectures for certain undergraduate courses from the University of California, Los Angeles (UCLA).
Open Learning Initiative | Harvard University Extension School brings free audio/video lectures on topics in computer science, English literature, history, and mathematics.
Video & Audio | University of Cambridge offers free access to audio and video lectures from the University's institutions including the Isaac Newton Institute for Mathematical Sciences and the Department of Materials Science and Metallurgy.
Podcasts from the University of Oxford provides free access to certain course materials and audio/video lectures on a variety of subjects, including chemistry, engineering, humanities, life science, medical sciences, physics, and social sciences.
YouTube - UHouston's Channel (University of Houston) contains lots of video lectures on various subjects: anthropology, chemistry, English literature, history, philosophy, and psychology.
nanoHUB Courses contains free educational materials about nanotechnology. The courses cover the following subjects: nanoelectronics, NEMS/nanofluidics, nanomedicine/biology, and nanophotonics.
Mathematical Sciences Research Institute (MSRI) provides a large number of free video lectures on a variety of subjects in mathematics and mathematical sciences.
CERN Document Server provides a huge collection of text documents and video lectures in particle physics and related areas.
Department of Mathematics, University of Colorado at Colorado Springs offers free video lectures on mathematics including calculus, discrete mathematics, linear algebra, differential equations and mathematical statistics. Registration is required to access the lectures.
Indiana Multimedia Distribution System offers free audio/video courses and lectures in business and management from Kelley School of Business, Indiana University Bloomington.
The pasted website has links to all the places, alternately, you could simply google the words in bold.