You need to download and install the Active Users Mod first. After installing and configuring, you can put a link in the top navigation bar to the active users page.
Have a look for the sForumNavigation sub in inc_header.asp, you can make changes to your menu there.
Search is your friend “I was having a mildly paranoid day, mostly due to the fact that the mad priest lady from over the river had taken to nailing weasels to my front door again.”