Magento : Get Current Package Name and Theme Name

// To get the current package name of the Magento store / site
Mage::getSingleton('core/design_package')->getPackageName();

// To get the current theme of the Magento store / site
Mage::getSingleton('core/design_package')->getTheme('frontend');

// You can pass 'locale', 'layout', 'template', 'default', or 'skin' into the above function.