Changing dev environment to Homebrew I'm a new mac user and I'm going to start using Homebrew to build my environment. My current environment I've installed piece by piece. What I want to check is what to make sure I do, so I don't get conflicts and i'm not running a load of software that I don't need.

Is this just a case of through the terminal uninstalling, apache, php, mysql etc and clearing out my usr/local/ folder and starting with homebrew?
You can leave your existing installations in place for the time being.  Homebrew will error if it has to overwrite an existing file in the process of installing a package.