Folks playing around with Exchange 2010 since its beta release were waiting for the RTM launch. Wait ends here. Today, Microsoft launched the Exchange 2010 RTM officially and can be downloaded from Microsoft Exchange Server 2010
Before you install Exchange Server 2010, Microsoft recommends that you review the summary of system requirements and technical information located in the Exchange Server 2010 Technical Documentation Library.
This time-limited version of Exchange Server 2010 will end 120 days after installation.
Learn more about Exchange Server 2010, visit http://www.microsoft.com/exchange/2010.
So download, install and enjoy testing!!