Open Source Windows Chat Software

BeeBEEP is a secure (encryption based on Rijndael Algorithm, AES) peer to peer office messenger. You can talk and send files with all your colleagues inside a local area network such of an office, home or internet cafe without a server. BeeBEEP works also with VPNs. This serverless application is indispensable in all those places where privacy and security an essential requirement. For more info visit: https://www.beebeep.net

DC++ is an open source Windows client for the Direct Connect file sharing network. The DC network is a decentralized network, made up of individual servers (hubs) that users join to share files with other members on that hub. Each hub is individually run by a fellow user of the DC network, and may have certain themes to the content on the hub. Hub owners set up rules to regulate their hub as they see fit.

EiskaltDC++ is a cross-platform program that uses the Direct Connect and ADC protocols. It is compatible with DC++, FlylinkDC++, LinuxDC++ and other DC clients. EiskaltDC++ also interoperates with all common DC hub software.

Coccinella is a free and open-source cross-platform communication tool with a built-in whiteboard for improved collaboration with other people.

dxirc is simple IRC client

Kadu is a dynamically evolving instant messenger compatible with the Gadu-Gadu and XMPP protocol. It can be run on all platforms supporting the Qt toolkit.

ISIM messenger is everything you need to stay in touch with friends from Skype, Facebook, Google+ (Jabber) and ICQ. ISIM doesn't contains any advertisements or so much functions. What ISIM gives to you? - chatting with anyone from protocols above in nice chat window with colorfull nicks and smileys - cotnact list with avatars, availability icons, unreaded messages indicator - calling, conference, video calls (just a test at the moment) and sending files though Skype