$dbAdapter = Zend_Db_Table::getDefaultAdapter();
					$authAdapter = new Zend_Auth_Adapter_DbTable(
						$dbAdapter,
						'users',
						'fname_user',
						'password_user',
						'MD5(?)'
					);

					$fname = $form->getValue('first_name');
					$password = $form->getValue('password');

					$authAdapter->setIdentity($fname)
								->setCredential($password);

					$auth = Zend_Auth::getInstance();
					$result = $auth->authenticate($authAdapter);
					$code = $result->getCode();

					switch ($code)
					{
						case Zend_Auth_Result::SUCCESS:
						{
							$identity = $auth->getIdentity();
							var_dump($identity);
							break;
						}