Here is the code that I am using:

var start = UI.createButton({title: "Record"});
start.addEventListener('touchstart', function(e) {
  recorder.start();
  start.title = "Recording...";
});
start.addEventListener('touchend', function(e) {
  file = recorder.stop();
  start.title = "Recorded: " + file.size;

  var xhr = Titanium.Network.createHTTPClient();

  xhr.onerror = function(e)
  {
    Ti.UI.createAlertDialog({title:'Error', message:e.error}).show();
    Ti.API.info('IN ERROR ' + e.error);
  };
  xhr.setTimeout(20000);
  xhr.onload = function(e)
  {
    Ti.UI.createAlertDialog({title:'Success', message:'status code ' + this.status}).show();
    Ti.API.info('IN ONLOAD ' + this.status + ' readyState ' + this.readyState);
  };
  xhr.onsendstream = function(e)
  {
    Ti.API.info('ONSENDSTREAM - PROGRESS: ' + e.progress);
  };
  // open the client
  xhr.open('POST','http://localhost:8097/v1/upload');
  xhr.setRequestHeader("Content-Type", "audio/x-wav");

  // send the data
  xhr.send(file);

});

It records, saves a file in the tmp directory with the contents and even reports the correct file size. When I try to upload though, the content length is zero.

Sam