An important part of managing Exchange, as well as scripting for it,
is knowing exactly what version is installed on each of your Exchange
servers. It's also good to know what versions of the Outlook client are
in use in your organization. There are several ways to gather this
information, but figuring out what build numbers and version number
correspond to which releases can get difficult.
The CDOLive website maintains a useful list of Exchange and Outlook build numbers, and they're keeping it updated. This is good stuff and useful to know. Thank you to the folks at CDOLive.