Windows Live Messenger
Windows Live Messenger is the next-generation MSN Messenger. It has everything you already love about Messenger—your contact list, emoticons, and instant access to your friends via text, voice, and video—plus new ways to connect and share photos and documents effortlessly. As always, it's free to download Messenger and use most of its features.
System Requirements
Supported Operating Systems: Windows Server 2003; Windows Vista; Windows XP
Pentium 233 MHz (500 MHz recommended)
128 MB of RAM (256 MB recommended)
Up to 50 MB of hard disk space for installation, 15 MB to run the program
Microsoft Internet Explorer version 6 SP1 or later must be installed on your computer, though it does not need to be your default.
800 x 600 or higher screen resolution
http://www.microsoft.com/downloads/details...ckInfoContainer
http://windowslive.com/Desktop/Messenger