Microsoft has released Service Pack 1 for MOSS/SharePoint 2007 and WSS 3.0, as well as the Office Client (which I posted earlier today).
Here’s an Overview of the Service Pack as well as a link to find out the issues that have been addressed in the Service Pack.
The 2007 Microsoft Office Servers Service Pack 1 delivers important customer-requested stability and performance improvements, while incorporating further enhancements to user security. This service pack also includes all of the updates released for the 2007 Microsoft Office System servers prior to December of 2007. You can get a more complete description of SP1, including a list of issues that were fixed, in the Microsoft Knowledge Base article 936984: Description of the 2007 Microsoft Office Servers Service Pack 1.
~ Robert Shelton