Ask News.YC: Thoughts on automating deployment of web based software application?

I work in a team of 3 developing a PHP based application and I am involved with developing a procedure for deployment. We have SVN for SCM and phpUnderControl for continuous integration. Our development, staging and production systems are Linux based.

I would like to know if there is a robust methodology for deployment that we can adapt.

Specifically, here are a few questions that I would like to have answers for: 1. How do you automate deployments (scripts used/ is there an app that does this)? 2. Rollbacks (including Database Rollbacks) - How do you handle it? 3. Is there a good Database Revisioning app?