Hello All,
I am a student sys admin and not a professional. I'd like to know how can I migrate the user accounts in the current server to a new server( to be installed) non-destructively. Also in what way the old server can be used after installation of the new server. I'd sincerely appreciate any helpful ideas and thanks in advance . 
Maybemedic.
You didn't mention what flavor of UNIX you are working with so I will tell you how to do it in AIX.
if you're moving to a brand new system with no users created yet you can simply move the following files to the new box from the old box (please create backup files at the destination before the copy):
/etc/passwd
/etc/group
/etc/security/passwd
/etc/security/group
Then backup their home directories and restore them at the new box.
Using SSH it can be this easy:
tar cvf - /home/user1 | ssh newserver " ( cd /home/user1 ; tar xvf - ) "
Also don't forget their cronjobs. These are located in /var/spool/cron/crontabs on AIX.
They may be fond of their email too so look for it in /var/spool/mail.
Good luck.
Thank you so much Dogday, Im sorry to trouble you again. The flav of Unix Im using is Linux (Redhat 7.1.2.96-98 to be specific). Anyway we are planning to use Suse 9.0 enterprise edition on the new server. I greatly appreciate your help and thank you for the help ur gonna do. :)) . Have fun.
Maybemedic.