This post describes how you can perform text field auto-completion with Zend Framework (ZF) and jQuery. To make full use of this post, you will need to have a working knowledge of Zend Framework and of jQuery. You don't need to be an expert at using them though cos if you do, you probably won't be reading this post. Here goes.
The basic assumptions here are that you've got your application running on the Zend Framework already and that your jQuery script is placed in the right place which means all your view scripts can access jQuery code.