Hi Brian,
I've actually seen both sides of this. I've used it myself both as a website owner and a website user. It's certainly something I see that can add value in the right circumstances.
For example my hosting company has a live chat facility and it's great to be able to talk to them to get real time answers to simple little questions rather than sending an email and waiting a while for a reply.
You do get chat software that allows you to pop up a box when some hits your site. I would say to avoid this sort of thing. By all means publicise the fact that you have live chat but I think it works better when the user instigates it.
I think the best idea would be to test it and see if it works. There are some free and some fairly low cost software options out there.
Lets us know how you get on if you decide to go with it
