Michael Mealling announced the release of the Internet Draft "A URN Namespace of Object Identifiers", which provides a means of creating unique URNs, building on enterprise numbers, which can be assigned through the IANA

The OID scheme provides a means for developers and companies to creating unique Uniform Resource Names (URNs) without having to handle a registration process of generating IDs linked to network card addresses, for instance.

OIDs are not intended to be 'resolvable' URIs, though infrastructure for such resolution could be created. Instead, the numbers are to be used to identify resources uniquely and persistently, without the overhead of a central registry. This should make them a good fit for the identifers used in XML namespaces.