Seriously, as others have said there is better ways of doing this.

Are you on a *Nix box? If so, you should be able to use tcpdump or ethereal or any kind of sniffer to figure out whoose making connections to ssh. Furthermore, you could use ntop to display a list of all incoming connections. Whether this would display a list of users, I doubt it, but what is the point of that anyways?

Why don't you do as others have suggested and take a look at working with SSH's log files. Hell, if you really want to get funky and generate some sort of report with perl, you could easily just manipulate what is inside of the logs to how you want to see it.