Microsoft has released a pre-configured VHD with Exchange 2010. This download lets you evaluate Exchange 2010 for 60 days. A 64-bit physical machine running Windows 2008 Hyper-V or higher is necessary for running the VHD.

Login details for the VHD is as follows.

UserName: contoso\Administrator
Password: pass@word1

Download the VHD here

http://www.howexchangeworks.com/2010/02/exchange-2010-vhd-for-evaluation.html