There have been several threads on the user and dev list following on from the recommendations made in the best practices document.
The objective is to make an artifact standalone, without the need to rebuild to deploy to a new environment. Configuration should be externalised (or all stored inside and selected based on an externalised parameter). This can usually be done with JNDI in J2EE (especially for database configurations), but this has a couple of limitations:
Some products to consider:
A couple other projects that might be of use are jConfig (http://www.jconfig.org/) for configuration management and SmartFrog for the deployments themselves (http://www.hpl.hp.com/research/smartfrog/)
And now controltier has been opensourced! http://open.controltier.com/