server.js

var child_process = require('child_process'),
    sys = require('sys'),
    net = require('net'),
    netBinding = process.binding('net');

var fd = netBinding.socket('tcp4');
netBinding.bind(fd, 8080);
netBinding.listen(fd, 128);

for (var i = 0; i < 4; i++) {
  // Create an unnamed unix socket to pass the fd to the child.
  var fds = netBinding.socketpair();

  // Spawn the child process
  var child = child_process.spawn(
    process.argv[0],
    [__dirname + '/worker.js'],
    undefined,
    [fds[1], -1, -1]
  );

  // For some reason stdin isn't getting set, patch it externally
  if (!child.stdin) {
    child.stdin = new net.Stream(fds[0], 'unix');
  }

  child.stdin.write(sys.inspect(fd), "ascii", fd);
  
  // Echo output from child
  child.stderr.addListener('data', function (data) {
    process.stdout.write(data);
  });
}

worker.js

var net = require('net'),
    http = require('http'),
    sys = require('sys');
    
sys.debug("Child started " + process.pid);

// var stdin = process.openStdin();
var stdin = new net.Stream(0, 'unix');
stdin.addListener('fd', function(fd) {
  http.createServer(function (req, res) {
    res.writeHead(200, {"Content-Type": "text/plain"});
    res.end("Hello from " + process.pid);
  }).listenFD(fd, "tcp4");
});
stdin.resume();