National Programme On Technical Enhancing Education [NPTEL] is an official website for developing technical education, funded by Government of India and maintained by IIT's and IIS.Seven IITs and the Indian Institute of Science (IISc) have worked together to develop web and video based material for basic undergraduate science and engineering courses in order to enhance the reach and quality of technical education in India.
As on today, it's offering about 260 courses( 125 Web assistance and 135 video assistance) are offered by this official site and has planned to offer about 500 courses to clearly explain all the basic concepts of Engineering.
The Official NPTEL Website has all the courses available for free viewing and download. Youtube (one among the official sponcers of this programme) has an IIT channel, from which all the courses (approximately 40 hours of lectures per course) are available free of Cost.
DVDs of individual courses (3 DVDs per course) is available from the NPTEL website. These can be obtained from the btechguru website.
Additionally, academic and learning institutions can also obtain the entire set of all courses by contacting NPTEL.
For viewing this site, go to this link. http://www.nptel.iitm.ac.in/