"Last I heard, Nathan was still learning PERL, but I believe he knows a fair amount of good ol' PHP."
Its the other way around
Well, heres how it works:
Steve installed an addon that handles chat. Chances are, its
possible to enter his chat without registering first, by having a link to a page that has the chat on it. Of course, if you put that page in your SMF directory, and build a PHP script, you could potentially apply a permission group to it.
The other thing about it is, what if someone wanted to invite someone else into the chat without having to register? Just sending them a link is the easiest way.
That, and if its IRC, anyone will be able to connect to it no matter what.
There is a PJIRC Addon for SMF, which could potentially be useful, but I think it would be best to just put a bunch of web-based IRC clients in one place, and let the user decide which one to use (as well as a link to an actual client, or two, for advanced users)
I will tell you this, Chris: SMF Is a blast to manage, its definitely got to be one of the better ones out there.