Multiple vnc instances on a linux machine !

Carlito - VNC user - installer
Thu Jul 3 13:51:01 2003

Yo !

I'm running vnc at the moment at it works beautifully , however in my
/etc/rc.local file I've put vncserver & and it starts up !
I enter the session password and I get my X desktop for root.

Now how do I retain that functionality but also allow another user ( john )
to also automatically open up his windows vnc viewer proggie and connect to
his X desktop , without via ssh starting up anything manually via a console
session ... 

In simple terms how do I run 2 vnc servers 2 times on one machine for
different users ?