I\'ve been looking for some guidelines on how to layout PHP code. I\'ve found some good references, such as the following:
http://www.dagbladet.no/development/phpcod
There's really not a single, common standard for these things. Most languages are more restrictive than PHP in this sense.
In the later years, a lot of so-called frameworks have emerged, and amongst other things they define a set of rules for everything from naming over where to place files and to which style your code should follow. There are several frameworks around, so you can't really pick one and call it the standard. However, most frameworks have a subset of commonality. For example, most follows some variant of the PEAR Coding Standards.