Reuters reports that Microsoft has announced plans to open up the code to their Office suite. Microsoft will share the code with 30 world governments, allowing them to inspect it for "security problems". The announcement is part of a wider "Microsoft's Government Security Program" launched last year, where 30 governments have been allowed access to the source code of Windows 2000, Windows XP, Windows Server 2003, Windows CE and now Office 2003.
Microsoft's main competitor in many markets is free software. More often than not, it's also open source (i.e. anyone can view the underlying code that makes the programs work). Microsoft programs are generally closed source and are only opened up to select people, often with tight restrictions.
To a certain extent, Microsoft has opened up the code to stay competitive (or ahead of the game) with regard to Open Source software. Asides from this fact, the problems with security and inter-operability with Microsoft programs has prompted the move. Governments often use and need software from a variety of vendors to work together to ensure efficiency. Microsoft hopes the move will restore any faith lost in the past few years; recently, the company has been beaten to some lucrative and high value contracts by Open Source alternatives.