Fantasy

Big Finish / Dark Shadows

Dr. Who /

Highlander

Stargate http://www.bigfinish.com/

Horror

Horror Theatre http://www.horror-theatre.com/

Monster Club http://www.themonsterclub.com/radiolibrary.htm

Science Fiction

Twilight Zone http://www.talkzone.com/archives.asp?sid=538

Anomaly Calling / Dry Smoke and Whispers http://www.drysmoke.com