My ramblings on the stuff that holds it all together
Location of Sysprep Files When you Install vCenter on a Windows 2008 Server
If you need to install vCenter 4 on Windows Server 2008 and want to be able to customize non Windows 2008/Vista and later VMs (i.e Windows XP, 2003, 2000) you need to place the extracted deploy.cab files in a different location than you used with Windows 2003 (C:\documents and settings\all users … etc.) so that vCenter has access to the sysprep.exe files.
On Windows 2008 this location is now in C:\ProgramData\VMware\VMware VirtualCenter\sysprep
You can then extract the deploy.cab file to the appropriate folder and use the customization specification functionality (like this ESX 3.5 example)
There is a handy reference with download links for all versions here.
Note – as I posted previously you don’t need to worry about this if you are solely deploying Windows 2008/Vista and later VMs, as they have sysprep.exe built into the default OS build.