GUID and LUIDs

[Doug Ransom <Doug.Ransom@pwrm.com>]

In the SOAP spec there is an example of a uuid stored in a tag.

 

<Id>uuid:C905E7ED-B616-4018-A547-1D6C70411BE0</Id>

 

is this a standard way to represent a uuid as a string?  How would I represent a locally unique identifier.