Need accounting(logins/logouts)help

[Szczypinski]

     I am a computer operator, not a programmer or administrator
officially. I basically learn what I can from other people. What I
need help with is the logins and logouts accounting files. 
     We have several secure silicon graphics machines in our area.
Right now for our standard practice we must have any users who login
to the machine sign in and sign out on a sheet of paper. What we want
to do is have that same procedure, but have it done automatically by
the system. I assume it has something to do with /etc/wtmp file, but I
cant make much sense of it. If someone out there has a similar setup,
could they please respond to this letter.    

                         Live long and Prosper- rjr