A family of Microsoft word processing software products for creating web, email, and print documents.
To see how to do this and just about everything else you might want to do with dates in Word, check out my Microsoft Word Date Calculation Tutorial, at:
http://windowssecrets.com/forums/showthread.php/154368-Microsoft-Word-Date-Calculation-Tutorial
or:
http://www.gmayor.com/downloads.htm#Third_party
Do read the document's introductory material. No mailmerges, etc. required.