app/code/community/Aoe/TemplateHints/Helper/Data.php
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 $content;
    }
public function getSkinFileContent($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;
    }
Get skin file content

@param $file
@return string