UTF-8

The simplest solution seems to be to use the utf8-string package from Galois. It provides a drop-in replacement for System.IO

import System.IO.UTF8
import Prelude hiding (getContents, putStrLn)

main =
 do putStrLn "what is your name? "
    name <- getContents
    putStrLn $ "hello, " ++ name ++ "!"