This is a very interesting article, because currenly  I have the same problem by converting the existing PHP application to Zend Framework. It is a very challenging process, all PHP were written by somebody else without any documentation. I have to open all the PHP files in the same directory (about 53 files), I have to read all the PHP code line by line in order to understand what the previous PHP programmers have done. And this blog has given me some ideas about the mirgration.http://www.buggy.id.au/2009/07/15/migrating-to-the-zend-framework/