code: public function getSkinFileContent($file) {
          $package = Mage::getSingleton('core/design_package');
          $areaBackup = $package->getArea();
          $path = $package
              ->setArea('frontend')
              ->getFilename($file, array('_type' => 'skin'));
          $content = file_get_contents($path);
          $package->setArea($areaBackup);
          return $content;
      }
docs: Get skin file content
  
  @param $file
  @return string