[CentOS] preparing to migrating to new system

Tue Dec 21 22:07:16 UTC 2010
Jerry Geis <geisj at pagestation.com>

hi all,

I will be migrating my mail server from centos 4.8 to 6 when its released.
Basically its just a number of users with their passwords. Their mail is 
downloaded to their clients
and not stored on the server.

What is the most sensible or correct way to migrate ALL the users to the 
new system?
Way in the past is was just perhaps copy the /etc/passwd file but I know 
thats not the case anymore.
how do I easily recreate their account names etc... on the new machine.

Thanks, for any advice.