MSXML

Here is how to perform an XSLT transformation and write the result to a file:

var outputStream = new ActiveXObject("ADODB.Stream");
outputStream.Open();
outputStream.Type = 1; // adTypeBinary
xmlDoc.transformNodeToObject(xslDoc, outputStream);
outputStream.SaveToFile("output.html", 2); // adSaveCreateOverWrite
outputStream.Close();