Sirc, the perl irc client, is a full-featured package to let you chat with anyone, anywhere in the world.

sirc has all the features you need in an irc client -- dcc, logging, and a huge ability to be customized are all part of the package.

with perl, it's quite simple to extend sirc's capabilities -- the programming interface is well-documented and well-developed. several example scripts are included in /usr/lib/sirc.