List of programs included in the Office XP product box (KB 290531) lists the programs included in the various Office XP versions.

"Office XP Small Business" is not shown, but appears to be the same(?) as "Office XP Standard" shown in this article.

"Office XP Professional" is shown as:

Contents: All the software included with Microsoft Office XP
          Standard plus the following software:

            - Microsoft Access 2002

Note that there also is/was an "Office XP Professional Special Edition" which differs.

John