Miranda IM is a free multi protocol instant messaging client that lets you connect to all popular instant messaging networks from one common place. Miranda IM supports Yahoo, MSN, AIM, Facebook chat, and much more. On top of that, you can extend the functionality of Miranda IM by using tons of plugins that are available for free.
[Also Read:7 Best Free Web Based Instant Messengers]
Here are some of the IM networks that Miranda IM supports:
and many more..
So, you can just install Miranda IM, and chat with all your friends on different chat networks.
I have reviewed many such All-in-one IM clients earlier, like, Pidgin, Digsby, and Trillian Astra. What I really like in Miranda IM is that it has tons of plugins available. You can extend the functionality of Miranda IM a lot by using those plugins.
Miranda IM is completely free, and a nice all-in-one IM.