Patch for DWR 2.0.1 (other patch is for HEAD)
Things to note.
engine.js uses a multipart post if one or more files are being marshalled
dwr.util.getValue() works for files (returns the javascript file object).
InboundVariable contains a FieldValue which may be a file or a string.
FileConverter can convert to org.directwebremoting.export.FileUpload or java.io.InputStream and is defined in the default dwr.xml file.
I have included an example in the webapp (at /fileupload/)
Support for beans with nested FileUpload properties.
I have tested in IE and firefox.
Patch submitted 21/6/2007