node.jsでhello world

app.js

var express = require("express"),                                                                                                                            
    app = express.createServer(),
    port = process.env.PORT || 3000;


app.configure(function(){
  app.use(app.router);
});

app.get("/", function(req, res){
  res.end("hello world!!");
});

app.listen(port);