Un petit script expliquant comment utiliser socket.io avec Express.
Le script en vrac ci-dessous au cas où :

/**

• Module dependencies.
  */

var express = require('express')
, routes = require('./routes')
, http = require('http');

var app = express();
var server = app.listen(3000);
var io = require('socket.io').listen(server);

app.configure(function(){
app.set('views', dirname + '/views');
app.set('view engine', 'jade');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.static(dirname + '/public'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(app.router);
});

app.configure('development', function(){
app.use(express.errorHandler());
});

app.get('/', routes.index);

console.log("Express server listening on port 3000");