on the original question, compile runs command make -k whihc isnt waht u want. goto the Options menu and click on edit Init File.
copy this into init.el:
(add-hook 'haskell-mode-hook 'turn-on-haskell-font-lock)
(add-hook 'haskell-mode-hook 'turn-on-haskell-decl-scan)
(add-hook 'haskell-mode-hook 'turn-on-haskell-doc-mode)
(add-hook 'haskell-mode-hook 'turn-on-haskell-indent)
(add-hook 'haskell-mode-hook 'turn-on-haskell-simple-indent)
(add-hook 'haskell-mode-hook 'turn-on-haskell-ghci)
save it.
Now you can use Ctrl-c Ctrl-l to toggle the ghci buffer
edit: btw this assumes that you have installed the haskell package for xemacs. to get it, you can dl the package using the users interface within Xemacs.