AdiIRC is an IRC client with multiserver support and a customizable interface. It offers all the standard IRC features including private chats, basic Identd features, sysinfo, and Winamp support. The program stores all it`s settings in text files and does not require an installation.
AdiIRC Features:
* Written in C# to be flexible and to implement neat features fast
* Threaded multiserver support
* 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
* Away system
* Channel text search panel (ctrl + f)
* Much more to come, stay tuned...

The license of this software is Freeware, you can free download and free use this irc client software.