Current user in Magento?

Found under “app/code/core/Mage/Page/Block/Html/Header.php”:

public function getWelcome()
{
    if (empty($this->_data['welcome'])) {
        if (Mage::app()->isInstalled() && Mage::getSingleton('customer/session')->isLoggedIn()) {
            $this->_data['welcome'] = $this->__('Welcome, %s!', Mage::getSingleton('customer/session')->getCustomer()->getName());
        } else {
            $this->_data['welcome'] = Mage::getStoreConfig('design/header/welcome');
        }
    }

    return $this->_data['welcome'];
}

So it looks like Mage::getSingleton('customer/session')->getCustomer() will get your current logged in customer 😉

To get the currently logged in admin:

Mage::getSingleton('admin/session')->getUser();