From the IBM Online Training Center (DevX.com) comes a new article covering the integration of PHP into a SOA solution:
With its fast deployment cycles, PHP is ideal for companies short on skilled programming resources and/or facing tight time to market deadlines. PHP's features and benefits are so compelling it should be considered for your SOA solutions.
They talk about the PHP integration kit that IBM offers to make using PHP as simple as plugging in things in the right places and how that would fit in with a "Service Component Architecture" and "Service Data Objects". They even give a simple example of a SCA component that works much like a PHP class.
They wrap up the article with a look at some asynchronous messaging with PHP - using the SAM extension to communicate messages back to the server for common tasks (like putting text messages in a queue).