I had been trying unsuccessfully for several days to install Darcs via MacPorts and Fink, but both seem to have trouble with the prerequisite GHC on OS X 10.5 (Leopard). However, I did find a very nice installer package for Darcs...
Been reading up a bit lately on Haskell and observing that there are a ton of monad tutorials out there. I've looked at a few and I have to say that my current favorite is: A Neighborhood of Infinity: You Could Have Invented...