A web based application that converts Excel files to a pre-defined XML schema

I need someone to develop an application with a web interface that allows a user to take an Excel spreadsheet and map the columns (with or without headers) and convert the data to an XML file that match the schema found on the website below: [login to view URL] It must meet the XML best practice referred to on the webpage and, where possible, identify any deficiencies in the data. The application must have an easy to use interface, be easy to use and look professional. I am not too concerned about the programming language as long as it is open source and can be used with all major modern browsers.