I have an later NC1000s which is a really nice camera - good lenses and feels a bit like an Olympus OM i.e. very compact and easy to handle.
A couple of good Mamiya 35mm websites are:
http://people.freenet.de/stauber/mamiya-nc/ - this site is dedicated to the NC series but does also have loads of stuff on the earlier M42 models such as yours. Text in English and German
http://herron.50megs.com/index.htm - a great resource for all 35mm Mamiya cameras