This paper provides an overview of deploying Exchange 2007 Server in a virtualized environment using VMware 3.5 Update 3 on Dell PowerEdge Servers and EqualLogic iSCSI storage array. In this paper a solution building block is proposed for 4000 mailbox users to deploy in an ESX environment running on Dell hardware. Various mailbox configurations of Exchange Server 2007 are tested to understand the sizing requirements for Exchange Server 2007 in a virtualized environment and validate the building block.