ircproxy is an advanced multi-user IRC bouncer written in C with IPv6 and
SSL support. It can proxy simultaneous users at the same time to different
IRC servers. The IRC connection can stay connected to IRC when the IRC
client disconnects, the user can then later reattach to the same IRC
connection.

Private messages and channel activity can an be logged when no IRC clients
are attached. You can then see what you have been missing while you're
offline. It is also possible to attach multiple IRC clients on the same
IRC connection. This is useful if you want to be connected from home and
work at the same time without cloning.

WWW: http://ircproxy.sourceforge.net/