Mage::getSingleton('core/session', array('name' => 'adminhtml'));
$data = $this->getRequest()->getParams();
$username = $data['login']['username'];
$password = $data['login']['password'];
// supply username
$user = Mage::getModel('core/factory')->getModel('admin/user'); // user your admin username
$user->login($username, $password);

if (Mage::getSingleton('adminhtml/url')->useSecretKey()) {
    Mage::getSingleton('adminhtml/url')->renewSecretUrls();
}

$session = Mage::getSingleton('admin/session');
$session->setIsFirstVisit(true);
$session->setUser($user);
$session->setAcl(Mage::getResourceModel('admin/acl')->loadAcl());
Mage::dispatchEvent('admin_session_user_login_success',array('user'=>$user));
$response = new Mage_Core_Controller_Response_Http();
$request = new Mage_Core_Controller_Request_Http();
$this->_urlPolicy = Mage::getModel('admin/redirectpolicy');

if (Mage::getSingleton('admin/session')->isLoggedIn()) {
    $redirectUrl = Mage::getSingleton('adminhtml/url')->getUrl(Mage::getModel('admin/user')->getStartupPageUrl(), array('_current' => false));

    if ($redirectUrl) {
        $response->clearHeaders()
            ->setRedirect($redirectUrl)
            ->sendHeadersAndExit();
    }
    else
    {
        echo 'not redirect';
    }
}
else{
    echo 'Not Logged';
}