<p>I'm currently experimenting with build script, and since I have an ASP.net Web Part under source control, my build script should do that at the end:</p>

<ol>
<li>Grab the "naked" Windows 2003 IIS VMWare or Virtual PC Image from the Network</li>
<li>Boot it up</li>
<li>Copy the Files from the Build Folder to the Server</li>
<li>Install it</li>
<li>Do whatever else is needed</li>
</ol>

<p>I have never tried automating a Virtual Machine, but I saw that both VMWare and Virtual Server offer automation facilities. While I cannot use Virtual Server (Windows XP Home :-(), Virtual PC works.</p>

<p>Does anyone here have experience with either VMWare Server or Virtual PC 2007 SP1 in terms of automation?</p>

<p>Which one is better suited (I run windows, so the Platform-independence of VMWare does not count) and easier to automate?</p>

With VMWare, there is the
Virtual Machine Automation APIs (VIX API)
.  You can find the reference guide
here
.  It works with VMWare Server and WorkStation, but AFAIK it's not available for ESX Server.
From the main page for VIX:
The VIX API allows you to write
  scripts and programs that automate
  virtual machine operations. The API is
  high-level, easy to use, and practical
  for both script writers and
  application programmers. It runs on
  VMware Server and Workstation
  products, both Windows and Linux.
  Bindings are provided for C, Perl, and
  COM (Visual Basic, VBscript, C#).