I can add a chatbox without issue, my only concern is that we use it more than we use the forums which actually hurts the site from a Google indexing standpoint.
If it's only to n00b it up then I'm all for it, if it detracts from forum topics then it's actually a detriment to the success of the website.
The only other limitation there will be is that everyone will need a minimum of 5 forum posts to use it. The reason for this is to keep the bots out of it because even as good as our spam controls are, some bots will continue to register.
I have a chatbox installed at Lifesupporters.com Forums called MGC Chatbox and am very familiar with it. It shouldn't take too long to install but I'll look at vBulletin.org to see if there is a more popular chatbox and update you all once I find/install something.