Xirc for MacOSX is an internet relay chat (IRC) application completely written in Cocoa-Objective C, it is compatible with Tiger (PPC/Intel) and Panther (10.3).
With Xirc you are able to talk with other people in the world, send and receive files with them. Xirc supports Audio Chat, DCC transfer, IPv6 and proxy connections (HTTP, v4, v4a, v5) and secure connection (SSL v2,v3). It is fully customizable and scriptable via AppleScript, Perl or using the powerfull like 'C' internal scripting language.
Xirc is under development but the current version is very stable and usable.