Till Gerken is a developer with over 10 years of experience in C programming. He has a strong background in creating high-performance multimedia systems and other medium to large scale, high performance projects. He currently works as freelancer for different companies. Tobias Ratschiller is a New Media Consultant in Italy, specializing in the creation of large scale dynamic Web sites. He has provided consulting and implementation work for some of the world¿s largest Web sites and has contributed to several other PHP titles. Apart from that, he teaches at seminars about usability, user interface design and content management systems. He runs http://phpwizard.net. Both authors have published Open Source PHP projects and technical articles for magazines like Internet World.