What tools/languages do you use for PHP web application deployment?
For PHP projects, Phing is the way to go. Deployment is definitely one of its intended usage, considering that in PHP there isn't any "real" build process - as scripts are not compiled.
From the official site:
If you find yourself writing custom scripts to handle the packaging, deploying, or testing of your applications, then we suggest looking at the Phing framework.
Phing can do everything shell/python/ruby scripts can do, and can be extended in PHP which is its major draw for PHP developers. Why would you want to use ruby/python if you are a PHP developer?