Exchange server SP2 is available for download – http://www.microsoft.com/download/en/details.aspx?id=28190
It includes the following features
Outlook Web App (OWA) Mini – OWA designed for low bandwidth
Cross-Site Silent Redirection for Outlook Web App
Hybrid Congfiguration Wizard – those who have combination or on-&-off premises Exchange server
Address Book Policies – For those who do hosting for different companies
And other customer requested fixes
Experience Microsoft Technology 