An ircbouncer to run on your shell:
http://freshmeat.net/redir/psybnc/84...NC2.3.1.tar.gz
.. and right, http proxies wont work in mIRC. mIRC wants a sock4/sock5 proxy.
Possible in theory to connect thruu a http proxy to a irc server(dunno if any clients supports it, I know some silly floodtools do) if they support CONNECT. I think most IRCservers have auto k-line on that though ... or just disconect when it sees it.