If you just want very simple hosting with CGI, NearlyFreeSpeech.net supports Haskell and some other less common languages. I personally also like their overall nonsense-free approach and sensible pricing model (pre-pay metered charges, instead of the usual model of a fixed monthly charge, oversold server capacity, and absurd overage fees).
There are a few caveats however, mainly that they don’t permit standalone servers or persistent daemons, only things invoked via CGI from Apache. This might be a problem for some Haskell web app frameworks.