In Word 2000 it's:
Menu: Table => Table Properties => Cell => Vertical Alignment
If you haven't messed with menu configurations, "Table Properties" is
at the bottom of the "Table" menu. If you are using "custom" menus in
a version of Word that supports them, wait a few seconds until all of
the bars on the Table menu appear. If you don't use "Table
Properties" often, it will "disappear" from the truncated menu that
appears immediately.
Fred Holmes