Microsoft Virtual Labs

Exchange Server:
http://technet.microsoft.com/en-us/virtuallabs/bb499043

Windows Server 2008:
http://technet.microsoft.com/en-us/virtuallabs/cc164207

Windows 7:
http://technet.microsoft.com/en-us/virtuallabs/ee862412

Lync Server 2010:
http://technet.microsoft.com/en-us/virtuallabs/gg720285

Sharepoint:
http://technet.microsoft.com/en-us/virtuallabs/bb512933

System Center:
http://technet.microsoft.com/en-us/virtuallabs/bb539977

Windows SBS:
http://technet.microsoft.com/en-us/virtuallabs/ff465366