The Office Team has released Office 2007 Service Pack 2 to the general public. Read about Outlook-specific changes here and download via Windows Update.
We have been running beta versions of SP2 in house for several months now and have found that it greatly improves performance and reliability. I highly recommend that you upgrade at your earliest convenience.
If you haven’t already installed the February Cumulative Update, SP2 will take several minutes to convert your Outlook mail file at startup. Trust me, it’s worth the wait.