Zend Framework is an open source PHP web application framework. It provides tools for building web applications using a model-view-controller (MVC) architecture. Key features include support for databases, email, web services, and integration with Zend Studio IDE. To get started with Zend Framework, install Zend Server which includes PHP, Apache, and the framework. Then create a new project, add the code to display "Hello world!", and view it at the local host URL. More information can be found on the Zend Framework and Zend Server websites.