On April 28, 2009, Microsoft released updates for Office 2007 via Service Pack 2. There are a number of knowledge base articles that review the updates and changes. You can find a comprehensive list of these articles at Office Sustained Engineering (a Microsoft blog).
If your system is set to update automatically, you probably already have the new service pack. To check, click the Office button, click the application Options button, click Resources, and then click About. (Outlook 2007 still has a Help menu.) If you don’t have it, click Check For Updates on the same page. Or download directly from Microsoft’s support site.
It’s only been a few days, but so far, so good. No one is reporting problems, as yet, with the update.