GHC 6.12 and MacPorts

I was getting the same error on MacOSX 10.5.8 when I installed haskell-platform-2010.1.0.1-i386 and attempted to compile a haskell program. The solution for me was to add the option "-L/usr/lib" to ghc when compiling the program. I believe this managed to get the linker to first search /usr/lib for the iconv library which resolved the problem for me.