If you're looking for a simple chat widget for you site or want to create your own, I recommend you to take a look at http://www.chatfarm.net.
It's a cloud service, that I've been developing for the last year. It provides 3 layers of integration:
- simple widget
- open protocol based on WebSockets
Here's an example of how you can create the widget:
The service is in beta stage and I will appreciate a feedback and will be glad to provide support for users.