node v0.6 cluster + express.js

server.js

var cluster = require('cluster');
var http = require('http');
var numCPUs = require('os').cpus().length;

if (cluster.isMaster) {
    // Fork workers.
    for (var i = 0; i < numCPUs; i++) {
        cluster.fork();
    }

    cluster.on('death', function(worker) {
        console.log('worker ' + worker.pid + ' died');
    });
} else {
    console.log("worker: %s", process.env.NODE_WORKER_ID);

    var express = require('express');
    var app = express.createServer();

    app.get('/', function(req, res){
        console.log("WORKED!! %s", process.env.NODE_WORKER_ID);
        res.send('Hello World');
    });

    app.listen(8000);
}