Andi announced on his blog the availability of Zend Server 6 on AWS MArketplace which allow developers to combine fees of AWS and Zend Server :

Now, for one combined fee with Amazon Web Services, you can run your applications on a fully supported PHP application platform with Zend Server 6 running on Red Hat Enterprise Linux or Ubuntu Linux.

zendserver6

Some of the key features of Zend Server 6 include Deployment Automation, Performance & Scalability, Monitoring & Root-Cause Analysis, Mobile-backend APIs, and more. Zend server 6 have been enterprise oriented with the addition of enterprise compliance and integration tools such Audit Trail, Role-based Access, LDAP Authentication Support,Easy Integration with 3rd Party Systems, and Customized Actions.

For more information about Zend Server : http://www.zend.com/en/products/server/