Simple Chat Rooms for my site?

Does anyone have advice about the best option for having a chat feature on my site, which is on shared hosting? I read the DH thing about no IRC. I don't like that much anyways.

I am using postnuke for my user registration and I've heard about PHPOpenChat and Flashchat among others. They appear to be not too bandwidth-intensive. Does anyone have experience with a chat program worth recommending?

(I also noticed Jabber allows for groupchat to be set up, but it looks like I'd have to manually add every user and each user would have to download a client to use it.)

I use one called Blab, nice, easy to use, easy to implement, multiple rooms, pm, etc.
http://www.hot-things.net/blab.php
it's not free though.

They do have a free one, blablite,
http://www.hot-things.net/blab_lite.php

Blab looks nice. For 'cheap and cheerful' - that is, no cost and nearly zero work for me, I've used Invision's free hosted chat: http://chat.invisionsitetools.com/free.php on a couple sites where I don't care much about integration. For example, I was able to drop a chat room into a forum topic on my family board using it.