The biggest advantange of XML is you can dynamically change data on the screen without having to refresh do an additional query. With XML you normally do 1 sql query and return the recordset and then you walk the DOM to find the data to display. XML can increase page load time because it has to do an extra step. But once the data is loaded into the data island is there until the user leaves. In other words, if you are new to php-leave it alone. Do database querys only. If you want to create extra fancy pages that can be changed by user input(ex. resorting a spreadsheet-like table by clicking any column.) I have been programming web applications for 5 years now and I honesty don't like XML for most things. It is very practical for use by companies that communicate with each other using different systems(ex. banks), other that, I don't have a lot of use for it. It is not the end-all language everyone believes it to be. It is specially designed to suit special needs as most languages are. If you want to learn XML go to this address:
http://www.w3schools.com
