A chatroom has been discussed in the past but I really don't like the idea of hosting this here on the site. I have a quite some experience with IRC (way in the past) and there's always so much crap going on in chat rooms.
Plus, the power of the forum is that everything is documented. Let's suppose user A has a tech issue and goes to the chatroom. User B guides him through the steps and they solve the issue. Great, but it's not stored anywhere for future reference. And that's just one example why I don't like the idea of a chatroom.
I like the idea of a "currently online" icon, but sometimes I also dislike the fact that folks can see when I'm online. Especially when people e-mail me questions and I don't have the time to answer them just yet. And then they see that I'm browsing the forum and wondering why I'm not replying to their e-mails
But seriously, I'll give this some thought. For now there a heck of a lot of other stuff I still have to finish for the site (like better IE support, haha) but let's keep this one on the ideas list!