Haskell Types

So I've been learning Haskell for some time, I get some basic and intermediate stuff, some monad basics, but could anyone recommend a good tutorial that explains type system better than YAHT?

>>29
getNums :: IO [Integer]

>>28
main = interact (unlines . map (show . product . enumFromTo 1) . takeWhile (0 /=) . map read . lines)