I understand that the live-action TV shows are separate from the comics, and that the recent/upcoming DC movies are separate from the TV shows, but do any of the shows share a continuity universe?
Before I stopped watching, the Green Arrow appeared in Smallville, and I remember hearing that the show Arrow was pitched as a spin-off, but I believe it uses a different actor.
I know there was also the short lived Birds of Prey series, and apparently Human Target is based off of a DC property as well.