Exchange Server 2010 SP1 is now available for download here.  Public announcement was made via the Exchange team blog here.

At Tech·Ed North America in June 2010, Exchange Server 2010 SP1 Beta was released to the public.  We are now announcing the General Availability of Exchange Server 2010 SP1 on August 25, 2010.  Exchange Server 2010 SP1 benefits customers with archiving and discovery enhancements, a faster Outlook Web App (OWA), upgraded mobility features, and several management tools improvements.

Good stuff!