Miranda IM is a smaller, faster, easier instant messenger with support for multiple protocols. Miranda IM is designed to be resource efficient and easy to use while still providing many features including support for AIM, Jabber, ICQ, IRC, MSN, Yahoo, and more. Supplemented by hundreds of plugins and other content, Miranda IM is very flexible and provides many avenues for customisation.
Miranda IM 0.6.6 brings bug fixes to improve stability. If you are using Miranda IM 0.6.5 or earlier, this is a highly recommended upgrade.