Microsoft has published Service Pack 2 for Office 2007, you can download it over here. This Service Pack includes all of the updates and hotfixes released through February 2009 and various other improvements like PDF and ODF support. Microsoft also claims various performance improvements, Outlook 2007 for instance has become 26 percent faster, and even 35 percent for users with large mailboxes. You can find the changelog over here.
Jane Liles, group program manager, Office Sustained Engineering, Microsoft: Users should notice the improved performance and stability of Outlook, better charting functionality in Excel, and more control over the appearance of SmartArt graphics.
On the server side, IT professionals will notice several enhancements to the security and performance of SharePoint Server 2007, including support for read-only content databases, improvements to forms-based authentication, and an STSADM command-line utility that enables administrators to scan sites that use the variations feature for errors. SharePoint Server will also feature better support for newer versions of the Firefox browser.
Also, having a wider array of file-format choices should really benefit customers. With SP2, Office 2007 now has built-in support for Open XML, ODF and PDF, along with the dozen or so other formats that were already supported in Office 2007.