I think I have the majority of the code that you'd need to set up a virtual observatory.

I'm working with some others on the Virtual Solar Observatory, and so far, all of our central architecture is Perl, as it was a common language between all of the project's programmers.

Our architecture uses the following components:

Registry

Contains information about all of the data providers in the system

Core

Acts as a 'switchboard', takes requests and sends them to the necessary data providers, and then assembles the responses from them.

Data Provider

Takes the given request, talks to a given archive (database, ftp server, etc.), and determines what observations may be of interest, and returns metadata about those observations.

User Interface

Anything that knows how to talk to the Core -- we currently have a few other VOs talking to us, a command line perl interface, a couple web-based interfaces, a command line IDL interface, etc.

I've been meaning to clean up the documentation and put everything into CPAN, but there hasn't been interest for it, other than as we get in new Data Providers (and they only need a small subset) who have to install the packages and deal with dependancies (SOAP::Lite, etc.)

(Some of our current work is in making the system more generic, to allow us to easily add new query / returned parameters, but it'd also allow you to replace all of the parameters with ones that were relevent for your field).