AdiIRC is IRC Client that can be used as free. Featured: Skin, Chat Room, Server Chooser, and many more.Written in C+ Language. Threaded multiserver support.
AdiIRC works as Portable IRC Client. Than means no need installation procedure. Just download, and then run it from the folder.
Full DCC Send/Get support
Sysinfo, like cpu,gfx,hd,mem,uptime etc
Winamp, iTunes, QCDPlayer and Windows Media Player now playing support
Fullscreen and opacity options
Rawlog output window
Channels/private windows logging
Customizable colors (inc mIRC colors)
Runs on all versions of Windows and out of the box in Windows Vista
Basic Identd features
Clean but customizable User Interface
Does not need an installer, everything stored in textfiles
Can update itself
Transparent background images
Channel text search panel (ctrl + f)