Microsoft Security Center - http://www.microsoft.com/security/

M$ Security Guidance Center - http://www.microsoft.com/security/guidance/default.mspx

Microsoft Security Guidance Center: Windows XP Index - http://www.microsoft.com/security/gu...WindowsXP.mspx

Webcast and Events for Security Training (I highly recomend to take a look) - http://www.microsoft.com/seminar/events/security.mspx

M$ Events and Webcast home - http://www.microsoft.com/seminar/events/default.mspx

Office Home Page - http://office.microsoft.com/home/

Office Trining - http://office.microsoft.com/training...EC790020111033

Office Templates - http://office.microsoft.com/template...EC790020111033

(Most links can be easily found in the ome pages, or a sub page, but sometimes without a direct link or point out we omit it since we look just as what is specific) [I do that all the time ]
And the most important page for IT is

Microsoft TechNet - http://www.microsoft.com/technet/default.mspx