Exchange 2010 RC is available for download
RC=release candidate=just about done
https://www.microsoft.com/exchange/2010/en/us/try-it.aspx
The key release themes, to help you position to your customers, are as follows:
- Flexible and Reliable
- Anywhere Access
- Protection and Compliance
You can get the product overview here: https://www.microsoft.com/exchange/2010/en/us/overview.aspx