VolusionLiveChat

This is a small application that allows you to interact with people who are visiting your website, it can be used to provide technical support (an online help desk), respond sales questions, etc.

This livechat is a good option if you have an online store, and need to help your clients decide if the product they are interested in is what they are actually looking for or not, or if you need a way to provide specific information to your visitors.

To get it working you need to download and install a chat client in your computer and place a piece of javascript in your webpage.

The free version has limitations, it doesn't allow you to have more than one operator, keep transcripts, track customer locations, or prompt customers to chat with you.

I have used it for a while and the service is good. If you use the free version, you will probably be constantly prompted to buy a solution with its developers, and personalization of client's chat window is very limited. Some free icons are available for download too.