How to rename files parsed by Formidable?

How does one go about naming files parsed by Formidable in Node? Currently my files are saving as '7c9d182a9892bb7588b49ea9d364efd0.pdf', I would much prefer the original file names.

Anyone know how to do this?

This is how I did it (check out the .on(file'...) function):

// import required modules
    var express = require('express');
    var formidable = require("formidable"); // used for parsing form data
    var fs = require('fs');

// prevent bodyParser from handling multipart forms (ie only handle get and post requests)
    delete express.bodyParser.parse['multipart/form-data'];

// create server
    var app = express.createServer();

// connect middleware
    app.configure(function() {
        // creates body object on request object
            app.use(express.bodyParser());
            app.use(express.methodOverride());
        // used to display static files such as css
            app.use(express.static(__dirname + '/static'));
    });

// enable and define views
    app.set('views', __dirname + '/views');
    app.set('view engine', 'jade'); 

//******************************
//* create routes
//******************************

// file upload handling
    app.get('/photos/new', function(request, response) {
        response.render('photos/new');
    });
    app.post('/photos', function(request, response) {
        console.log('in /photos handler');
        var form = new formidable.IncomingForm();

        form.uploadDir = __dirname + '/static/upload/photos/';

        form.on('file', function(field, file) {
            //rename the incoming file to the file's name
                fs.rename(file.path, form.uploadDir + "/" + file.name);
        });

        form.on('error', function(err) {
            console.log("an error has occured with form upload");
            console.log(err);
            request.resume();
        });

        form.on('aborted', function(err) {
            console.log("user aborted upload");
        });

        form.on('end', function() {
            console.log('-> upload done');
        });

        form.parse(request, function() {
                response.render('photos/new');
        });
    });

// start our server
    app.listen(8888);