The above package is for Intel Leopard... it should be possible to build packages on Leopard that run on both Tiger and Leopard. (I could give that a try if anybody with a Tiger box is willing to play guinea pig.)
I volunteer. What do I need to do?
Try this http://www.cse.unsw.edu.au/~chak/haskell/GHC-6.9.20080213-i386.dmg It's a quick build of todays HEAD with only the boot libraries. Have a look whether that installs on Tiger (I am pretty sure it will) and whether you can run /usr/bin/ghci (not so sure about that). If it works that far, please compile some small Haskell program and see whether you can run the compiled program. If we are very lucky and all of this works, please try to compile ghc itself with the compiler in the package. Thanks, Manuel PS: It's a dmg this time around, because apparently only 10.5 packages are single file archives.