Based on heartland's recommendation I have tested Providesupport.com's Live Chat software. I was initially impressed, but the deeper I dug the more problems I found. Here are a few major ones:
-No logging. Period. Once a user exits your site you will have no way of tracking when they were there and where they went. You could, of course, do this with other tracking software (such as Google Analytics or Urchin), but it would be nice to have a "history" in Live Chat.
-The web based operator console is missing a lot of functionality.
-The "cobrowser" function will not work with

carts. Now I could be wrong about that statement, because my

cart doesn't have an SSL certificate and changes domain names during checkout, but Live Chat tech support told me that cobrowsing won't work with "cookie tracking", only "session tracking"
-The online admin interface is confusing, the full featured. You'll waste a lot of time looking for menus and links.
Other than those gripes I like the software. There is a kind of perversion associated with watching people browse your site in real time without them knowing. Being a network administrator I have the constant urge to "kick" people off of my site for one reason or another, which, unfortunately the software cannot do.
I also just tried ChatStat and took it down with 15 minutes. Even when testing it on my own machines internally it didn't display every message I typed. Try typing two or three messages within a second or two and most (if not all of them) will be dropped. The chat client software was also extremely distorted for me, which I don't have time to troubleshoot.
-SC