Miranda NG is the smaller, faster, easier instant messenger with support for multiple protocols. Designed from the ground-up to be resource efficient while still providing a rich feature set, Miranda includes support for AIM, Jabber, ICQ, IRC, MSN, Yahoo, Gadu-Gadu and more. Additionally, with the choice of hundreds of plugins, icons, sounds and other content, Miranda NG gives you the ability to modify, customise and extend functionality to make it your own. (Source: Miranda-IM.org)
The Sebijk Edition has been greatly expanded, supports more protocols and has a user friendly interface.