Quickstart: Zend_Session

Bootstrap:
Zend::register('session', new Zend_Session());

Write some value
Zend::registry('session')->value = $value;

Read some value
$value = Zend::registry('session')->value;

Use isset
if(!isset(Zend::registry('session')->value)) {
Zend::registry('session')->value = $value;
}