The usual way to do this is to have a parent process that is essentially always blocked on accept, with child processes that do the actual work. Fitting this into your framework would be something like this:

while ($client = $server->accept()) {
    $pid = fork();
    if ($pid == 0)
    {
        print $client "Welcome to $0";  # etc.
        # Probably a loop here reading from $client
        # ... Other stuff
        exit 0;     # Remember to go away when done!
    }
    # parent process here
    close $client;
} # and go back to accept.
[download]

One thing missing from here is a throttle. You want to keep a count of active child processes so you don't keep creating new ones without any limit. Incrementing the counter is easy; the trick is to decrement the counter properly when each child process exits. In unix-land you can trap SIGCHLD for that, I don't know the equivalent on Win32. Whichever method you use, be careful to single-thread access to the counter. In other words, make sure when two children exit "at the same time", the counter really is decremented twice.

I haven't looked at the modules for handling forks. They may well solve this problem for you.

HTH