Modest
A good starting point when initially learning about XML. This example shows a simple XML file and a simple XSL file that transforms the XML file into HTML for display as a Web page.
Moderate
An interesting second step that takes the modest XML/XSL files and creates a Navigation Menu and multiple Web pages from one XML file by modifying the XSL.
Elaborate
Here's something closer to a real-world example that combines multiple XML files and XSL files to control the content, presentation, and maintenance of Web pages.