I saw this over at the The Official SBS Blog and thought I had better tell everyone about it given the traffic on the web page. Once you apply this patch you might get an BCM (Business Contact Manager) error if you have installed it - to fix this, go look at My BCM Updates Post and grab the one about "Outlook 2007 with Business Contact Manager: Prevent error message about version mismatch when certain Office 2007 applications are launched".
[Today's post comes to us courtesy of Mark Stanfill]
There is a new patch available for Outlook 2007 that fixes performance issues with large PSTs/OSTs. We highly recommend applying this patch on all systems with Outlook 2007 installed. If you are preparing a new installation, this patch should be applied in addition to the steps outlined in http://support.microsoft.com/default.aspx?scid=kb;EN-US;926505 .
Source: The Official SBS Blog : Outlook 2007 Update Available
Fri, May 4 2007 9:30 AM