Hi Michael,
UNSPSC (United Nations Standard Products and Service Code) is an international coding system that helps to classify products and services. It has over 45,000 terms for classifying products and services. UNSPSC numbers can be used for classifying devices (SG.inventory) according to the international standard code.
For more information about how to use UNSPSC in ServiceGrid visit:
http://docwiki.cisco.com/wiki/ServiceGrid_Article_-_Common_Content#Product_Classes_.28UNSPSC.29
Find more information about UNSPSC on Wikepdia: http://en.wikipedia.org/wiki/UNSPSC
Regards,
Alex