VIOPS VMware Icons and diagrams
Visio stencils made from the artwork as released by the official VMware branding team. Can be used for documentation, now also includes vSphere artwork.
VIOPS: Visio Stencils for vSphere
and
http://viops.vmware.com/home/docs/DOC-1338
Unfortunately these visio stencils have disappeared, even after asking the VMTN team about this a couple of months ago, they are still gone. An alternative can be found here: Technodrone: My Visio stencils again There's a few other places on the web with visio templates, see the category below for more or search for visio. Update on Maish's his Visio stencils: New vSphere vision stencils