hi ,
Firstly why can't the no admin guys use ssh ? its just a way of connecting to the server securely.
You have to make sure if you have any firewalls in place they allow port 22 (ssh) through from the server and install ssh on the server and start it up
secondly you edit /etc/inetd.conf file and comment out telnet and refresh inetd.conf
try telnetting you'll be refused ?
From PC what ever emulation s/w you use set it up so that your session uses ssh and not telnet , if your emulation s/w does not support ssh you can download putty which is free
If you desperately need telnet , then all you need to do is install ssh and one way to stop other users telnetting to the server is in the users profile check if they have telnetted ( uses something like lsof / ps -ft (tty) ) and if they are then print message "please you ssh" and exit
For the users who can use telnet then leave ther profiles as they are
hope this gives you some / bit more info