Microsoft Windows SharePoint Services 3.0  Service Pack 2 (SP2) and Microsoft Office SharePoint Server 2007  Service Pack 2 (SP2) include updates designed to improve performance and availability in your SharePoint server farm, along with fixes to known issues across SharePoint Products and Technologies. In addition, SP2 provides enhancements designed to support greater interoperability, improve user experience and reduce administrative burden. Finally, SP2 provides the groundwork for an eventual upgrade to the next major version of SharePoint Products and Technologies.

WSS 3.0 and MOSS 2007 Service Pack 2 also incorporates all the previous major updates, including Service Pack 1 (SP1), the Infrastructure Update, and all of the cumulative update packages up to and including those released in February 2009.

Following are the main Features included in the WSS 3.0 and MOSS 2007 Service Pack 2 (SP2):

1. Performance and Availability Improvements
Service Pack 2 includes many fixes and enhancements designed to improve performance, availability, and stability in your server farms, including:

  • Improved database performance and integrity by automatically rebuilding database indexes with a timer job.
  • Improved user experience by automatically configuring site collections as read-only when the content database is configured as read-only.
  • Performance enhancement across nearly all the components

2. Improved Interoperability
Service Pack 2 continues to improve SharePoint interoperability with other products and platforms.

  • Broader support of browsers. Internet Explorer 8 is added into Level 1 browser support and FireFox 3.0 is added into Level 2 browser support.
  • Provide improved client integration user experience with Form Based Authentication. Now the client application can store user credentials instead of asking for them every time.

3. New STSADM command line operation
A new preupgradecheck operation is added to stsadm tool. It can be used to scan your server farm to establish whether it is ready for upgrade to SharePoint Products and Technologies. It identifies  issues that could present obstacles to the upgrade process. It also checks for SharePoint Products and Technologies system requirements, including the presence of Microsoft Windows Server 2008 and a 64-bit machine, and provides feedback and best practice recommendations for your current environment, together with information on how to resolve any issues that the tool discovers.

In addition to operations for pre-upgrade scanning and variations analysis and repair, several operations are improved and new operations added to better support farm administration.

4. SP2 makes it easier to configure Excel Web Access Web Parts on new sites. Several rendering, calculation, and security issues have been resolved. SP2 also offers a range of improvements for users of InfoPath Forms Services. Performance enhancements in SP2 reduce both the memory requirements and the page load times for large browser-rendered forms. SP2 also improves the browser rendering of various controls, such as the Cannot be blank red asterisk and the rich text field.  

You can find a lists the issues that are fixed by this service pack at http://support.microsoft.com/kb/953338.