Pidgin is a free chat client that helps you message all of your friends across popular IM software applications from one centralized location.

Meebo—an instant messenger application that integrates multiple web chats, G-chat, MySpace, AIM, MSN and Yahoo!—has now integrated facebook chat as well.

If you use instant messaging as a way of communicating in your organization, you may want to consider this app which provides the first visual chat collaboration platform built around a group -- instead of the typical linear one-on-one chat format.