title: How to implement service layer in Zend Framework?
body: <p>I'm looking for some good resources to learn how to implement internal service layer in Zend Framework. <a href="http://www.angryobjects.com/2009/03/30/writing-robust-php-backends-with-zend-framework/" rel="noreferrer">This is interesting post</a> <a href="https://bmark.us/bmark/readable/e02284a08d351e" rel="noreferrer">Bookie Link</a>, but with no concrete code samples.</p>
  
  <ul>
  <li>Where to put service classes (<code>/application/modules/modulename/services/</code>?);</li>
  <li>How to autoload them (custom autoloader?)</li>
  <li>Most common services (user, authentication, cart, cache, feed?)</li>
  <li>Sample implementations (any github repos?)</li>
  <li>Good practices?</li>
  </ul>