More information is starting to flow about the Office2003 Beta 2 Refresh:
You should test Exchange 2003 RC1 with Microsoft Office Outlook® 2003 along with the Office Technical Beta Refresh that will be available through Microsoft Office Products Update in June.

Caution: Do not run Office 2003 Beta 2 on Exchange 2003 before installing the Office Technical Beta Refresh.

Download Exchange 2003 RC1: https://microsoft.order-6.com/exchrc1
Information: http://www.microsoft.com/exchange/evaluation/ti/rc1.asp
Order the Microsoft Office System Beta 2 Kit 2003 : http://www.microsoft.com/office/preview/orderbeta.asp