There is a new IVOA Note available entitled:
"Virtual Observatory Architecture Overview",
by Roy Williams, Bob Hanisch, Tony Linde, Johnathan McDowell, Reagan Moore, François Ochsenbein, Masatoshi Ohishi, Guy Rixon, Alex Szalay, and Doug Tody.
The paper is available at the IVOA web site http://www.ivoa.net/Documents/Notes/IVOArch/IVOArch.html
I would like to thank all the authors and commentators from the IVOA Architecture Working Group for their hard work and collaboration in the preparation of this document.
Please address comments and edits to architecture-at-ivoa.net for infcorporation to version 1.1 of the paper.
Roy