I had to prepare a meeting on virtualizing Exchange 2007 on a VMware VI3.5 environment. While searching the internet I found an enormous amount of pdf’s and whitepapers and decided to share them with you:
VMware.com:

Deploying Microsoft Exchange in VMware Infrastructure
16,000 Exchange Mailboxes, 1 Server – VMware VROOM!
Virtualization Solutions for Exchange Server 2007
Advantages of Virutalizing Exchange [...]