Ernest Borgnine does the voice for Mermaid Man on Sponge Bob SquarePants and Tim Conway does the voice of Mermaid Man's side kick, Barnacle Boy.
Mark Hamill of Star Wars fame did the voice of the Joker in Batman: The Animated Series.
I know these are not kids shows per say like Sesame Street or Blue's Clues but they are the only ones that I can think of right now. lol.