IRC

asuka
Development page of the IRCd used by QuakeNet.
http://dev.quakenet.org/

Beware ircd
A small (less than 200 KB) IRC server for Windows that is able to handle large numbers of users.
http://ircd.bircd.org/

Blitzed Open Proxy Monitor
BOPM is an open-source open proxy monitor which works with the Hybrid, Bahamut, Xnet, Unreal and Dancer IRCDs.
http://wiki.blitzed.org/BOPM

ChatSpace
Commercial chat server for small to mid-size businesses.
http://www.chatspace.com/

ConferenceRoom
Popular commercial IRC server for Windows.
http://www.webmaster.com/

DALnet - Bahamut
Bahamut is an Internet Relay Chat Daemon (IRCd) designed for DALnet, one of the major IRC networks in the world.
http://bahamut.dal.net/

DALnet IRCD
The DALnet FTP archive. More than just IRCDs.
ftp://ftp.dal.net/pub/dalnet/server/

The DarkFire IRC Daemon
The server software used on the DarkFire IRC Network. A robust IRCd based on Dreamforge with enhancements and years worth of changes.
http://ircd.darkfire.net

Faerion
An open source multi platform IRC server developed with respect to internationalization and portability.
http://faerion.sourceforge.net

FWS IRCd
Windows IRC server with a reasonable amount of configuration/tweaking options. It also has VBScript support, a built-in HTTP server (IRCd information), IRC Services, DNS server, client graph program, many IRC tools and some IRC clients.
http://ircd.fwsnet.net

IgnitionServer
An open source/free RFC1459 compliant IRCX server for Windows with services (NickServ, ChanServ, etc.) and remote administration.
http://www.ignition-project.com/

The Inspire IRC Daemon
InspIRCd is a C++ IRC Daemon for Linux and BSD systems. The system is modular and scalable and includes a module API.
http://www.inspircd.org

IRC Defender
IRC Defender is a fully modular perl program which helps with securing a medium to large network against abusive users, bot attacks, and ban evasion.
http://ircdefender.sourceforge.net

IRCD
Release notes, free download, documentation and FAQ for the (now historical) original Internet Relay Chat Daemon.
http://www.nic.funet.fi/~irc/server/

IRCXpro
IRC server for Windows. Free trial version, FAQ, manual, reviews, example sessions. Also offers messenger client.
http://www.ircxpro.com/

Old IRC Depository at cs-pub.bu.edu
Out of date distribution site; for historical purposes only.
ftp://cs-pub.bu.edu/pub/irc/servers/

The Perl IRC Daemon
News, view CVS tree, mailing lists, readme file, and source downloads.
http://pircd.sourceforge.net/

TR-IRCd
An IRCd that combines the comfort of bahamut with the reliability of hybrid, adding user security related features.
http://tr-ircd.sourceforge.net/

UltimateIRCd
IRCd based on dalnet DreamForge IRCd.
http://www.shadow-realm.org/

Undernet IRCD
The Undernet IRCD server.
http://coder-com.undernet.org

UnrealIRCd
One of the most feature-packed IRC servers in the world.
http://www.unrealircd.com

UnrealIRCd Modules
Contains several modules for UnrealIRCD which add new commands such as an improved banlist, bad word filters and anti-spam filters amongst other features.
http://www.angrywolf.org/

Windows IRC servers
Several (outdated) IRCDs compiled for the Windows Platform.
http://www.storer.net/ircd.html