[Haskell-cafe] monoid fold concurrently

Hello, I would like to create a fucntion whcih does mkCube :: [IO a] -> IO a mkCube = ... I want to fold all this concurrently in order to obtain the final a I have a function like this merge :: a -> a -> IO a in order to sort of merge two a into another one. I did not found something like this on hoogle. so I would like your advices in order to write mkCube Thanks Frederic