Windows

Editors

• Emacs, Vi(m), etc
• Visual Haskell
• Eclipse

Compilers

• WinHugs
• GHC : Special note for Cygwin users - http://www.haskell.org/ghc/docs/latest/html/building/platforms.html

Libraries

• GUI : WxHaskell (new release in progress, goal < 2007-01). Note, see also WxHaskell Install
• Win32 - low levelish bindings to Windows API. Comes with ghc and non-minimal hugs distribution. Win32 darcs repo

Special tips and tricks for Windows

• darcs : http://wiki.darcs.net/index.html/WindowsConfiguration (although darcs send seems to be broken for now [2006-08-30])