The major prerequisites for Exchange Server 2007 are .Net Framework, MMC 3.0 and PowerShell installed before we deploy Exchange Server 2007.
.Net Framework and MMC 3.0 features have already installed in the Windows 2008 by default, so we have to install PowerShell and to accomplish this task we have to follow these steps:
Open Server Manager (Start/ Administrative Tools/ Server Manager)
Click on Features, then click on Add Features
Choose PowerShell on that list, and then click Next
Final screen of the Windows PowerShell installation
Now, we have to wait the Exchange Server 2007 SP1 to deploy Exchange Server 2007 on Windows Server 2008, but all Exchange Server 2007 prerequisites are done :)