Hi,
You will find tens, hundreds of scripts, procedures, tips, hints etc. at:
http://www.iiug.org
By the way you can get a list of database users from the following SQL statement:
select username,
case
when usertype="C" then "Connect"
when usertype="R" then "Resource"
when usertype="D" then "DBA"
else "Unknown Usertype"
end usertype
from sysusers;
onstat -l will show the list of currenly logged ones from that list.
Regards,
Shriyan