I am the principal designer and developer of wxHaskell. The goal of the project is to provide an industrial strength GUI library for Haskell, but without the burden of developing (and maintaining) one ourselves.
wxHaskell is therefore build on top of wxWidgets – a comprehensive C++ library that is portable across all major GUI platforms; including GTK, Windows, X11, and MacOS X. Furthermore, it is a mature library (in development since 1992) that supports a wide range of widgets with the native look-and-feel, and it has a very active community (ranked among the top 25 most active projects on sourceforge).
See wxhaskell.sourceforge.net for more information about wxHaskell
"Oct 18 2005"