On PHPMaster.com today there's a new tutorial about using the Zend_Pdf component of the Zend Framework to generate invoices from the billing data in your application.

The PDF format is currently the most used format to exchange documents. If you provide your website users with printable versions of invoices, event tickets and other similar documents, you’ll most likely want to generate them as PDFs on the fly. In this article you will see how you can use Zend_Pdf to auto-generate PDF invoices.

The concept is pretty simple - take the rows of invoice data from your system and inject them into a new PDF document. They show you how to create an invoice layout that includes that data, a header with your company name, invoice-related information and the total/amount due at the bottom. The full code is included to help you create the Zend_Pdf object, apply the text to it (based on location in the document) and working with the default font. You can download the full source from github.