In a new article today on PHPMaster.com Robert Mariotti takes a look at standards and how important they can be when developing applications (both in following them and defining them correctly). It's not specifically targeted at PHP developers, but it does give some good food for thought.
As a long-time programmer, often with a staff of other programmers to watch over, I learned early in my career how important enforcing programming standards is in contributing to the overall success of a project. Not only do standards affect an individual's production of code, but they ensure that anyone else who may contribute code later can do so with a reasonable expectation of consistency.
He defines the abstract concept of "coding standards" as rules or guidelines that should be followed based on the application. Sure, there's more global standards for things (PSR-0 anyone?) but your needs will always be different and more fine-grained than those can get. He recommends standardizing everything, possibly using one of the standards popular open source projects have already laid out as a base.