Captain Video’s passing (Richard Coogan, the first actor to play Captain Video, beginning in 1949) reminded me that science fiction, fantasy and horror fans have at least two great reasons to love the internet – the Internet Archive and Project Gutenberg.
Over at the Internet Archive, you can find all manner of clips, television show episodes, serials, full length films and radio plays (not to mention texts as well). The links below will reveal collections of these materials specifically put together for fans (presumably by fans):
Science Fiction & Horror Film Collection
Old Time Radio (1) (2) (3) (4) (5)
Magazines (many more, but here is a link to the complete archive of Starlog Magazine)
Archive.org has plenty of texts as well (comics, magazines, books), but the real place to go if you are looking for texts is Project Gutenberg:
They’re both good places to find things you may have missed as well as a window into our genre past.