The oldest website dedicated to media history is Media History Project. This site hosts nowadays a large collection of digital sources. Amongst that a collection of radio magazines form long ago.
Beautiful is the website that connects the BBC to its own history. Maybe even better is the website of the archive of Canadian public service broadcasting CBC. A lot of films and radio clips are online. A bit in low resolution, but varied in content. The national archive of Canada hosts a beautiful website with films to be looked at in the style of old cinemas.
In the Nethgerlands the website of the Hilversum based Instituut voor Beeld en Geluid is the first spot to get to know radio history. Together with radio historians they have build up a website that connects to all radio stations in the world: radio garden.
That media history even can be commercially attractive is shown by Old Time Radio. Do you want old radio drama on your MP3-player? Or do you prefer the collected radio speeches of Franklin D. Roosevelt? Here’s the place to get them….