[Haskell-cafe] map in IO

[Tom Hawkins]

What is the best way to perform a map inside IO?  I defined the 
following function, but this must be common enough to warrant something 
in the standard library.  What am I missing?

-Tom

mapIO :: (a -> IO b) -> [a] -> IO [b]
mapIO _ [] = return []
mapIO f (x:xs) = do y <- f x
                     ys <- mapIO f xs
                     return (y : ys)