HTML template processing with PHP

Hi I am completely new to PHP. For some upcoming projects I have to get familiar with it. First I would like to know whether there exist some PHP based software packages/libraries that allow to process HTML templates/files by providing methods to fill input fields or plain text into custom tags, or by allowing to loop over HTML areas in order to build tables/link lists out of database contents. I heard of some XML parser library (mentioned in the PHP docs), but which seems to be something quite basic, I'd like to know whether there exists something more advanced. Thanks for every pointer. bye Sam Jordan