This script can be used to integrate the Haskell build into Xcode.
Instructions for doing this are in GHC-iPhone.pdf

--- ghc-6.10.2.orig/cabal-install/cabal-install/build-iphone-haskell.sh	1970-01-01 12:00:00.000000000 +1200
+++ ghc-6.10.2/cabal-install/cabal-install/build-iphone-haskell.sh	2009-06-18 15:54:37.000000000 +1200
@@ -0,0 +1,34 @@
+#!/bin/sh
+echo "build-iphone-haskell.sh running with ACTION=$ACTION and PLATFORM_NAME=$PLATFORM_NAME"
+
+IPHONE_BIN="$(dirname $0)"
+DIST="$TARGET_BUILD_DIR/dist"
+export PATH="$IPHONE_BIN:$PATH"
+
+case "$PLATFORM_NAME" in
+  iphonesimulator)
+    CABAL=iphone-simulator-cabal
+    ;;
+  iphoneos)
+    CABAL=iphone-cabal
+    ;;
+  *)
+    echo "build-iphone-haskell.sh: No cabal version for platform '$PLATFORM_NAME'"
+    exit 1
+    ;;
+esac
+
+case "$ACTION" in
+  "")
+    mkdir -p "$DIST" || exit 1
+    $CABAL --distpref="$DIST" configure || exit 1
+    $CABAL --distpref="$DIST" build || exit 1
+    ;;
+  clean)
+    $CABAL --distpref="$DIST" clean || exit 1
+    ;;
+  *)
+    echo "build-iphone-haskell.sh: Unknown action '$1'"
+    exit 1
+    ;;
+esac