Some interesting interviews from Star Trek actors and people associated with the show can now be seen at the Archive of American Television website.
The interviews, other than one with LeVar Burton, are from the original series.
Included are regulars Leonard Nimoy, William Shatner, LeVar Burton, Nichelle Nichols, and George Takei; as well as guest actors Elinor Donahue (Metamorphosis), Ricardo Montalban, Diana Muldaur, William Schallert (The Trouble with Tribbles), and Jane Wyatt (Journey to Babel).
Some topics include: Shatner on why Star Trek had such a strong following, Nimoy on Spock’s make-up, Burton on getting cast for Star Trek: The Next Generation, Takei on Star Trek going off the air, and Montalban on Khan.
Others associated with the franchise; including writers, composers, directors and special effects people include: Joseph M. Wilcots, Fred Steiner, Herbert F. Solow, Ralph Senensky, Hank Rieger, Richard Matheson, Robert Justman, Gerald Fried, Dorothy Fontana, George Clayton Johnson, Robert Butler, Leo Chaloukian, Alexander Courage, Elinor Donahue, and Gerald Perry Finnerman.
The interviews can be found here. Specific Trek-related parts of the discussion are highlighted, but fans can go back to the beginning of the interviews (which are usually several parts long) and watch the entire interview, which will include non-Star Trek work.