A new site called bibleybob.com gives the ability to add a chat room to your WordPress blog. All you need to do is...
1. Create a room for your blog on bibleybob (just type the room name in!)
2. Click Options and then Share Chat to get the iframe code
3. Create a new page on your blog and paste the code in (select HTML)
Working example at http://www.neggs.com/?page_id=185