frontConfiguration.class.php

<?php

require_once(dm::getDir().'/dmFrontPlugin/lib/config/dmFrontApplicationConfiguration.php');

class frontConfiguration extends dmFrontApplicationConfiguration
{
  protected $request;

  public function configure()
  {
    $this->getEventDispatcher()->connect('request.filter_parameters', array($this, 'filterRequestParameters'));

    $this->getEventDispatcher()->connect('dm.layout.filter_stylesheets', array($this, 'filterStylesheets'));
  }

  public function filterRequestParameters(sfEvent $event, $parameters)
  {
    $this->request = $event->getSubject();

    if (preg_match('#Mobile/.+Safari#i', $this->request->getHttpHeader('User-Agent')))
    {
      $this->request->setRequestFormat('iphone');
    }

    return $parameters;
  }

  public function filterStylesheets(sfEvent $event, array $stylesheets)
  {
    if('iphone' == $this->request->getRequestFormat())
    {
      // Add, remove, change $stylesheets
    }
    
    return $stylesheets;
  }