Assuming a Yellow Dog Linux install on the Sony PS3, you can get working ghc binaries (in rpm form) for ppc from Fedora Extras Repository
To build from source, (assuming you have installed a ghc binary package already) you may find the default ./configure detects the system as powerpc64-unknown-linux. This blew up for me when compiling StgCRun.c with assembler junk at end of line, first unrecognized character is `@' errors. The fix is to pass an argument to configure to force a normal powerpc build ./configure --build=powerpc-unknown-linux.
Build time was about 8 hours (with extralibs), including a couple of hours on the penultimate source file to be compiled.