Lets be careful. Just because you have the font in YOUR Windows or OS/X installation does not mean you are legally allowed to replicate that font to other people or systems.
Take a look at
http://www.microsoft.com/typography/...y.aspx?FID=304 where the options listed are
- License the fonts for Enterprises, Web Developers, Hardware/Software redistribution or Server installation
- Purchase and download Microsoft fonts for personal, professional or business use on workstations