Best way to embed an IRC client in a webpage

I'm looking for a good, free, preferrably open source, IRC client to be embedded in a web page.

The obvious requirements of supporting most browsers, if requiering a plug-in it should be a plug-in that is allready widley deployed and it should not put too much strain on the webserver serving the page.

Which program is used for an IRC client software?

There are a wide variety of IRC client applications. The free open source software Mozilla web browser includes a built-in IRC client application called ChatZilla! which provides a good basic capability.

Not really a programming question, but Mibbit is quite capable, I've used it for a few different applications, it's always worked well.

Note that it will work best if your channel is on one of the networks listed here that support WEBIRC.