On DesignLuv.com today they've posted what they call a style guide for PHP developers - some types on writing well-styled, easy to read code.

If you’re a new developer and are trying to hone in on your coding style, maybe try giving the following a go. These are simply some conventional formatting methods that are generally appreciated and supported by PHP developers and will improve the overall readability of your code.

They talk about a few different subjects - variable names, class and method naming, bracket spacing, default arguments, constants, loops and a lot more. It's good to see them including things like commenting and file name suggestions.