I have used ProvideSupport with out any problem at for about a year. They are really good remotely hosted live chat solution. Great header and button graphics to choose from too.

If you want to host your own, I just recently decided to try out stardevelope Live Help script for multiple domains. It is working out really good. One thing tho is that their new app does not work for older OS like my Win2k, but they do have a version that we could use, just not the most recent.

I decided to host my own, simply because I do not get a lot of chats and I am not worried about timing out the server or slowness. But if I had a lot of chats, I would go back to remotely hosted.