On DZone.com there's a new post from Giorgio Sironi with some of his tips for PHP developers that want to use VIM in their development - some handy tricks to help make you a more effective developer.
In the case of PHP development, you'll need to add some configuration and plugins to speed up your activities. Most of the responsibilities of an IDE - like testing and version control - are outsourced to the terminal while running Vim; however, there are some tweaks that make writing and editing code faster, along with aiding in discovery classes and methods in a PHP codebase.
He includes settings for your .vimrc to detect and load the right PHP functionality, using Command-T, functionality for autocompletion and the snipMate plugin for managing and using reusable code snippets.