After you install this update, you can use Mac OS X Sync Services and Spotlight searches to sync and find Entourage items, use smart cards with Entourage 2004, and enjoy improved overall security and stability when using Microsoft Word 2004, Excel 2004, PowerPoint 2004, and Entourage 2004. This update also includes all of the improvements released in all previous Office 2004 updates.

Make sure to read the Exchange Users section - data loss is possbile if you move MBs.

http://www.microsoft.com/mac/downloads.aspx?pid=download&location=/mac/download/office2004/Office2004_11.2.3.xml&secid=4&ssid=29&flgnosysreq=True