miau is a fully featured easy to use IRC-bouncer that can keep your nick
even when you disconnect.

Additionally, miau can set you away automatically when you disconnect and
auto-op (or auto-voice) people. While you're disconnected, miau can also log
everything and/or pipe private messages to an external program. And when you
connect miau again, miau can replay some of the old messages so that you know
what's going on.