High Quality Content by WIKIPEDIA articles! Windows Live Messenger (formerly named MSN Messenger) is an instant messaging client created by Microsoft that is currently designed to work with Windows XP (up to Wave 3), Windows Vista, Windows 7, Windows Mobile, Windows CE, Xbox 360, Blackberry OS, iOS, Java ME, S60 on Symbian OS 9.x and Zune HD. The client has been part of Microsoft`s Windows Live set of online services since 2005. It connects to Microsoft`s .NET Messenger Service. The client was first released as MSN Messenger on July 22, 1999, and as Windows Live Messenger on December 13, 2005. In June 2009, Microsoft reported the service attracted over 330 million active users each month.