The Office Sustained Engineering team has released the list of updates that are included in Office 2007 Service Pack 3 (SP3). Office 2007 SP3, which was released in October 2011, includes a roll-up of all Public Update (PU) and Cumulative Update (CU) releases since Office 2007 SP2, as well as stability and performance improvements. Note that Office 2007 SP3 does not contain the October 2011 PU or the October 2011 CU.
For the updates list, see the Microsoft Office Updates blog (http://blogs.technet.com/b/office_sustained_engineering/archive/2011/12/09/office-2007-service-pack-3-roll-up-list.aspx).