Firefox plans bundling Mibbit as the default IRC handler in next release.
Mibbit is likely to become the default handler for irc:// and ircs:// in a forthcoming release of the Firefox browser starting with English language versions followed by a roll out of European and possibly more.
When the new release is available Firefox users will be able to chat instantly with a simple click to load Mibbit in context without worrying whether an IRC client is installed on the PC or configured manually in Firefox config. For users of MMOGs or just casual access to IRC people will be able to get to chat with other people faster.
We’re looking forward to this being available, until then check this article for details of how to configure Mibbit as the default now. mozillalinks.org
You can also download the firefox nightlys here: