This service pack contains all the Cumulative Updates and Public Updates for Office 2007 that have shipped since SP2 for both the Office client suites and applications, and the SharePoint server applications. The Project Server updates are included along with the SharePoint updates in the Office Servers SP3 updates. SP3 also contains additional new fixes which are described here. For a list of changes for each product, please refer to their individual KBs. The KB Articles referenced below will be updated throughout the day to include the live links to the published articles.
For your convenience here are the direct download links to the service packs:
As usual you have to install as well the service pack for the core product and for all installed language packs.