For the most part I do PHP scripting in Zend Studio and HTML/CSS in Dreamweaver. Depending on what I'm scripting for, I either follow PEAR/PHPDoc or Drupal/Doxygen formatting guidelines. Unfortunately, the most noticable difference is spacing. PEAR uses four spaces, whereas Drupal uses two.

I learned PHP by programming a content management system called Thatware (originally ThatPHPware) in 1998. Even though I've abandoned Thatware, it was forked several years ago by Fransico Burzi to create PHP-Nuke and all of it's forks. Naturally, as a novice programmer, Thatware is full of lots of "creative" hacks and duplicated code.