Web Browser Chat Software

Quick question for you all.

I am wondering if there is a piece of software that I could purchase to be able to allow people to chat on a website that I am developing. Now this would have to be done in the browser like at yahoo. Also I want to be able to customize this and to be restricted to a database of members.

Basically I am looking to create a members site, and when a user logs in they can use the chat. In loging in they could see others profiles etc.

thanks for the help.

Wow, I know how to install a chat program by using java applet, php, cgi, etc. Just go to
http://www.hotscripts.com

But create member section, create logins, etc I have no idea.