Trying to understand this... acting as primary&secondary for other domains

[Robert Chalmers]

I'm trying to understand how to set up a server so it acts as primary and
secondary for 'other' domains.
Like in the case of DomainRegistration services? I know how to set up the
Bind/zone files etc for my own domains, but if I was to say allow parking of
other domains, would I have to assign each of them one of my IP numbers from
my C Class set? Which wouldn't work anyway, as they would be part of my
address .... not possible,

So I couldn't have 'master' records for them.. So I'd have to set up
'slaves' or 'forwarders' .... or what.

Can anyone give me a clue as to how this is done, it's a facinating thing.
Because then one can also have Apace web pages attached, as they ofter are -
the 'free' sites with 5Mb etc.??

Thanks for any clues,

Robert