Hi there,
I don't know exactly how much help this will be, but here is a GCC+MUI tutorial I used.
http://www.ezcyberspace.com/gccThe first 2 lessons are mainly about GCC (although there are some bits about compiling MUI on GCC, which I don't know if it applies to MOS GCC or not) The lessons afterwards take you through some different aspects of MUI, building up to a basic program that has network support.