Elliotte offers: Managing XML data: XML catalogs
I like: Norm Walsh's piece.
In 2005, Norm and friends brought out this, which is the 1.1 version. (March 05). They unthinkingly seem to have published it in PDF only. How ill mannered of them.
Catalogs (as in library catalogs, not XML catalogs)
Just in case you got here thinking this was about library catalogs, its not. Peter gave us this set of references.
Dublin Core is much in vogue these days. Before you jump on that bandwagon and use DC for your repository, please bear in mind that DC was designed for easy information discovery and exchange on the net, not for precise and dependable cataloguing.
Do spend some time considering when and how you update the catalogue, and how you want to search, publish, or otherwise exchange information in the catalogue.
A few bibliographic links that I find interesting:
UKOLN Metadata ukoln.ac.uk
DESIRE Metadata Registry ukoln.ac.uk
Online Computer Library Center oclc.org
RefDB refdb at sourceforge
The XML catalog mechanism should provide the functionality you need. See Norm Walsh's article at Arbortext. Robin has kept a local copy too, see the cover pages. and the more recent copy at the sun site. Just in case :-)