How does one get about converting an excel file to an XML file given a specific schema?

Question

Is this something I need to write or something already exists. Google is pulling up a bunch of junk.

Answer 1

At the risk of totally missing the point, did you already try File -> Save As, and then choosing type=XML?

When you go to save, click on the HELP button, top right, and select file type. It will step you through saving XML using an XML Schema file (.xsd), and then talk about how to map the data properly.