Berlin Philharmonic's Digital Concerthall streams live videos of concerts and maintains a large archive — some at a fee, some for free. Among free services is a wondrous storehouse of 164 lectures and interviews with some of top artists of today.
The lineup includes — naturally enough — Berlin Philharmonic Music Director Simon Rattle, Thomas Quasthoff, Peter Sellars, Karl-Heinz Steffens, Daniel Harding, Christian Gerhaher, and many, many more.
A few examples: Rattle speaks about Witold Lutoslawski, Herbert Blomstedt on Beethoven and Nielsen, Jaap van Zweden, Riccardo Chailly, Christian Thielemann speaks about Verdi ...
Closer to home (as if geography mattered on the Internet), the San Francisco Symphony offers a Watch, Listen & Learn, a group of special video programs, and pointers to other SFS website. Also, there is the Symphony's YouTube site with many music videos.