Ask YC: Client work development workflow

I work in a small custom dev shop. We do drupal hacking, wordpress bits and some zen stuff. Then custom when we can't leverage open source.

We're looking to revamp our work flow from, build, test, deploy and then remote edit through ftp, hoping we don't screw anything up to svn controlled, locally developed, staged and then checked out of svn to a live server.

We're not sure the best approach to take and if there is software or resources out there to help us out?

Thanks.