The Microsoft page has all of the details on upgrade requirements:
<
http://www.microsoft.com/mac/howtobuy.aspx?pid=upgrade>
The page indicates that as the owner of a previous version of Office for
Windows, you are entitled to upgrade pricing on Office 2001 (the OS 8/9
version), but not Office X (the OS X version).
You could buy the upgrade version of Office 2001 and then purchase the
upgrade version to Office X if you desire the OS X version of Office, but it
would probably be easier to just buy a new copy of Office X if your machine
has OS X, because then you'll still get the next version, Office 2004, free
when it becomes available:
<
http://www.microsoft.com/mac/default.aspx?pid=office2004tg>
