Today is the official “Launch” day of Exchange Server 2010. With that great news, comes other news. The Exchange Server 2010 Bits will be available on the TechNet subscriber download site sometime today. Also, the evaluation bits for Exchange Server 2010 and Forefront will be available for download around 10 AM PST today. I would highly encourage you to go grab the bits and give them a try.
Exchange Server 2010 trial: http://go.microsoft.com/?linkid=9694893
Forefront Protection 2010 for Exchange: http://go.microsoft.com/?linkid=9694679
Since I am posting this a little early in the day, the above links may not be live just yet. If that is the case, come back some time after 10 AM (PST).