I've seen this KB article: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=100559...
It says "Microsoft has a different version of Sysprep for each release and service pack of Windows" and that we need to put the sysprep files in directories named 2k, xp, svr2003, etc.
What if we plan on making templates for multiple service packs of each OS? For example, XP SP1, XP SP2, XP SP3, etc?
Or will the sysprep files from XP SP3 work on all previous service packs?
Additionally, what about the difference between 2003 R1 and 2003 R2?
The latest sysprep files for XP, XP 64, 2003, 2003 64 should work for any prior service pack revision of those OSes. Also, 2003's sysprep covers 2003 R2 customization, since R2 in Server 2003 isn't really a different OS version per se, just an add-on pack that is installed after Server 2003 is set up.
Please note that VMware may not support deploying the earlier version of the XP/2003 service packs since those OSes have been out of support for quite a while. You would need to check the compatibility list for the version of vSphere you are using.
For Server 2008/Vista and newer, sysprep is built in to the OS, and you do not have to worry about copying the sysprep files to the vCenter Server.