I've got access to an IBM RS/6000SP system, with the Power3 CPUs. I'd love to see GHC up and running on this system. According to the list of working ports, this wouldn't be too hard to get working.

Has anyone tried doing this? Are there any tips for how to begin?

No one has tried recently, as far as I know. A good place to start would be to read the recent discussions on this list regarding porting to PowerPC/MacOS-X. The basic idea is to get the system up and running "unregisterised" first, which can be done with just a C compiler on the host system, then try to get the registerised bits working. The MacOS X port is still at the unregisterised stage, but they have a problem with a seriously crippled gcc. Asuming AIX's gcc is ok, it's just a case of updating a few bits & pieces, and possibly pulling in some small bits of code from the GHC 3.X runtime. We'll be happy to help out along the way. Cheers, Simon