Identify VMs which have no assigned "Tag"

Hello.

Since vSphere 5.1 and the introduction of the webclient I am working a lot with the feature "Tag" which can be assigned to certain identities (e.g. VMs)!

Unfortnately I still find VMs (created by other admins...) which no assigment of an Tag......

Does anybody know how to parse the vCenter inventory for VMs which don't have an tag??

or

Is there any way to assign an Tag to an template which be automatically assign it to the VM??

Thanks for responses!!!!