[Haskell-cafe] Bit fiddling

I'm toying a bit with Haskell and wondering what's the best way to implement bit fiddling. Most of my applications involve serializing and deserializing small blobs (IP packets, for instance), and after browsing the GHC library documentation, I'm not sure which appraoch I should use. That's why I'd appreciate pointers to sample code. Portability beyond GHC is not required. It's not necessary to update blobs, only to parse them, and serialize new ones. And in the beginning, I'd like to write the boilerplate manually. 8-)