@Desolator:
MUD programming is very dependent on the type of driver and mudlib you want to code for. You say you've played NannyMUD: I recall this MUD one uses LPC as its underlying language. You will want to look for Descartes' Basic and Intermediate LPC guides. They are a bit hard to find, but I found them
here. There a few hands-on guides scattered throughout the Internet, try Google-ing for them. There is no real tutorial for the language itself: a sound knowledge of C and OO principles will get you very far, though. (Think Objective C rather than C++ here.)
Coding your own LP-type driver is not easy. It comes down to creating your own compiler and bytecode interpreter. You might want to try coding a mudlib first. I know that
MudOS works just fine on (classic) Amigas, and that there are a few native MUDs available on Aminet. I do not know whether these are of the LP-type, though. Finally, the
Pike language was originally based on LPC. I don't know how much of LPC remains in Pike, and whether it runs on Amigas at all. But you might want to check it out nonetheless.
Anyway, be prepared for a lot of coding: it takes a lot of effort to get a MUD going. But good luck!