I am a PHP programmer for over 5 years. I've worked with PHP mixed with HTML, used with OO, and also with various frameworks (ZEND, Cake, Symfony, etc), Web Services. It was easy to learn php language, but to use it correctly and professionally took 2 years.
Now I'm programming in ASP.NET with VS 2008 and see major differences. Surely ASP.NET is much more robust, with several facilities. PHP has much to offer, despite being an easy language to learn, but has not as productive and robust tools. Zend has been engaged to form a robust framework and the Eclipse community a productive IDE, but both projects are still children compared to. NET and Java. For large projects advise ASP.NET or Java EE, but for small projects, PHP does very well (PostgfreSQL + Apache + PHP + Zend Framework + Eclipse). But the choice will depend on the team and the project size. Ben