Microsoft is currently working on SP2 for Office 2007 and could be ready to release a final version as early as this month.
Today an early copy has leaked to BitTorrent according to Windows Vista Magazine.
The file weighs in at 287.14 MB and is named office2007sp2-kb953195-fullfile-en-us.exe. It's not clear whether the leaked copy is a beta, RC or final version of SP2 but the EULA states "012.0_B2TR_PRE.0_BTA_EN" meaning it it's likely to be a test version. The build number is 12.0.6416.1000, compared to Microsoft Office 2007 SP1 which has the build version of 12.0.6331.5000.
SP2 will support Open Document Format (ODF), XML Paper Specification (XPS) and Portable Document Format (PDF).