I'm building a JBoss 3.0.x help site as I'm learning it...
I'ts got links to various tutorials and javadocs for the JBoss api. The site is:
FYI.. I've updated it a bit to include a guide/tutorial for getting source from cvs using wincvs and building it, initial guide on clustering and other stuff. There's also javadocs for jboss 3.0.4 api.