RetroShare is a Open Source cross-platform, private and secure decentralised communication platform.
It lets you to securely chat and share files with your friends and family, using a web-of-trust to authenticate peers and OpenSSL to encrypt all communication.
RetroShare provides filesharing, chat, messages, forums and channels
New features (DHT, Channels, Network View)
Improved stability w.r.t. previous version 0.5.0g"
Added lots of improvements, check for details svn log entrys
Tools and Utilities
Product page: here