The History of Microsoft feature on channel9.msdn.com is very cool. It gives you a brife history overview of Microsoft starting with 1975. This episode is for the year 1990, with the description of this show:
For Microsoft, 1990 is about communication as we announce the integration of voice messaging capabilities into Microsoft Mail for AppleTalk Networks. WinMail, a Windows version 3.0-based mail front end is available for internal use and Russian MS-DOS 4.01 is the first Microsoft product localized for the Soviet market.