Its going to air where I am on January 29th at 8pm. Not sure if it that will be the case across the country, but it is something to check your local listings for.
Here is the official description of the episode:
"Superheroes" crosses many eras: "Superman" in the 1950s, "Batman" in the '60s, "Wonder Woman" and "The Incredible Hulk" in the '70s and "The Greatest American Hero" in the '80s. The episode features in-depth interviews with Adam West, Burt Ward, Julie Newmar, Lynda Carter, Lou Ferrigno, William Katt and others. It also includes comments from Robert Culp, about his show "The Greatest American Hero, " recorded just days before he passed away.