Chris,
Here are a few links that I have collected over the months. Although, like I told you the other day, I have not personally integrated a chatroom into a website before. From what I have read however, if you are using one of these Java-based IRC clients to connect to an existing IRC server, it will not hog the web server as much. The problem seems to come when you are hosting a private IRC server on the same machine as the web server. Then it is a big bandwidth hog. These Java-based ones are just kinda like a "gateway" to the existing IRC servers, so might be worth checking out. Here are some links:
CGI:IRC (still an early version though)
Webmaster, Inc. (makers of ConferenceRoom)
IRC Client for Java(made by Alphaworks)
--deftech