Does anyone know of a program for OS X that can get the files out of a M$ style .cab file?

I have a Lego Mindstorms kit, but of course the CD is M$ only. Now this is fine, I have NQC as a replacement for the lego software, but I need to get at the firmware file do d/l it to the RCX. I downloaded one from the lego site, but I think it's beta firmware and I'd like to get hold of the dist that came with my kit.

Phew, a lot of babble for a simple question!