IRCXpro
IRCXpro is an Internet Relay-Chat (IRCX) Server that allows IRC clients such as mIRC to connect to your computer as an IRC based chat server. IRCXpro is rich in features such as server-to-server linking, remote administration, message content filtering, auditing, transcript logging and much more. ... IRCXpro is ideal for providing technical support to your clients, internal communications for your business, hosting live events over the net and online communities.
http://www.ircxpro.com/ircxpro.exe - 5Mb - Download - Screenshot

Vypress Chat
Vypress Chat is a user-friendly application for real-time chatting in small or home office (SOHO) local networks. This unique chat software features an easy-to-understand format for text-based conferences and discussions. Vypress Chat does not require an Internet connection or a dedicated server... You get an interface comparable to mIRC's graphical IRC interface, and system tray functionality similar to that of ICQ. ... Also available is IP Multicast protocol support. ... The IP Multicast allows Vypress Chat to operate over WANs or in complex routed network environment.
http://www.vypress.com/ftp/VyChat21.msi - 2Mb - Download - Screenshot

AntiFirewall Anonymizer
Connect to Newsgroups, FTP, IRC, ICQ and Email (POP/IMAP) even if you are behind a firewall blocking access to these programs/protocols. AntiFirewall will penetrate the firewall and connect to the Internet address of your choice, making it possible for you to read and post to News and use FTP,... IRC: Chat with your friends using standard IRC programs like mIRC even if access to the IRC protocol is blocked by your firewall; your IRC connection is anonymous, i. ... your IP address is hidden from the IRC network and other IRC users.
http://www.inetprivacy.com/ftp/antifrwl.zip - 400Kb - Download - Screenshot