On October 25, Microsoft released Microsoft Office 2007 Service Pack 3. KB Article 2591039 (http://support.microsoft.com/kb/2591039) contains technical details about SP3, while 2526086 (http://support.microsoft.com/kb/2526086) contains general information. Because Office service packs are cumulative, you do not have to install Service Pack 1 or Service Pack 2 before you install Service Pack 3. Service Pack 3 includes all fixes which were included in Service Pack 1 and Service Pack 2.
Service packs typically do not contain cumulative updates (CU) that they are released with, but they will contain previous cumulative updates. The last cumulative update was August 2011, which is included in SP3. Those installing SP3 for Office 2007 should be aware that the August Cumulative Update for Excel contained a problem that caused internal hyperlinks to be broken with the use of the ForceShellExecute registry key. This problem is fixed in the October Cumulative Update for Office 2007 which was just released. This fix is located here (http://support.microsoft.com/kb/2596545).