There are many IRC clients available out there, many that handle multi-server connections.
mIRC is probably the most crap available and doesn't. I think its only redeeming feature is its large range of scripts available.
Some IRC clients you might like to look at.
Pirch98 (my fave, but not reliable on win2k)
Klient (looks ok but quite complex to set up properly)
Trillian (lot of ppl seem to like this)
Xircon (no idea)
mIRC (sux
)
and there are probably lots more less known ones out there