Where should I store module-specific configuration information? It should be accessible to the admin.
In my case it's the root path for the Photos repository for the photos module.
It could be in the MBean config xml, or it could be in a custom table in the DB accessed by EJB entity.
In the first case it could be configured through JMX, in the second case, a config page should be created.
What is the "standard" way in the nukes project?
simple : module specific :
mbean attribute, we do support persistence in database for them for known types : primitives, XML, url, properties, etc....
now we have a nice JMX console better than the one provided by jboss. it's fully integrated with nukes.
business data : in DB through EJBs.
so for your case : mbean Attribute