XML is a great medium for representing data in a simple, platform-independent format. However, for most applications it's not want you want to present to your users. There are several technologies that provide ways to display XML; among them, XSLT is probably the most popular. XSLT, in a nutshell, requires the creation of an XSL template file that is used in conjunction with the XML document and a piece of software called a transformation engine to produce the final, displayable version of the XML.

If you're a fan of Java, Sun also has an XSLT Compiler that enables you to replace the transformation engine with a Java class. The XSLT Compiler works by parsing the XSL template file and creating a Java class that performs the translation that would typically be done by the transformation engine. It looks pretty neat, so check it out:
XSLT Compiler