Yahoo! Messenger - Instant messaging allows you to quickly exchange messages with your online friends. Unlike e-mail, instant messages appear as soon they`re sent. By downloading the Yahoo! Messenger application to your computer, you can send instant messages to other people from around the globe, send them files or have a voice conference. ... more

This is Windows Live Messenger version 2009 aka Windows Live Messenger 9, the latest version of Windows Live Messenger from Microsoft. WLM, right now, is in beta stage, so ONLY beta testers will be able to sign in!
Today, shortly after 0 AM, the latest Windows Live Messenger Build has been leaked. This Build features WPF effects and has a well designed User Interface
Install Instuctions:
Download, unpack, launch either the live insaller or just launch the messenger.msi ... more