We've got a pair of Christopher Reeve video interviews (in which he proves why he still owns the part), one from a 1979 appearance on The Tonight Show with Johnny Carson, the other conducted after he agreed to do Superman IV (but before production actually began). Additionally, there's the little-seen George Reeves Superman adventure Stamp Day For Superman, and the first part of an early '80s British documentary chronicling the history of Superman, featuring comments from, among others, creators Jerry Siegel and Joe Shuster.
Just click on the image below.