the PHP equivalent of 'use strict' (at least with respect to variable declaration) is setting the 'register_globals' configuration option to false. in PHP 4.1, the default for this setting in the distributed php.ini files will change from true to false. i don't know if the PHP community will adopt this recommendation, or continue on with potentially broken and insecure code.

also, using the E_NOTICE warning level will get error reporting similar to -w for Perl (variables used before they have an assigned value, potential precedence problems, etc.).