At my company we’ve been using server virtualization with VMWare products for 2-3 years. During that time we’ve created processes and procedures that allow us to deploy a server and its supporting operating system in as little as a few minutes. My reading suggests it is the same with the Hyper-V and XEN virtualization products as well.
Unfortunately, obtaining software licenses for the applications that we run on these servers can and does still take many weeks. The procurement process remains basically unchanged.
Although we’ve been taking this into account and It may be obvious to many others, you’ll want to be sure that you take the software and license procurement time into account when establishing project plans.
As an aside, we have one “well-known” vendor that keeps sending us 90-day temporary licenses for a product that is paid for and the check has cleared the bank.