In the first edition of Programming Perl there was an example program called receptionist which provided similar functionality to inetd. Of course it is perl 4 but despite the fact that you would probably do things differently now it is still a good example.

The examples can be found at ftp://ftp.ora.com/published/oreilly/perl/programming_perl/perl.tar.Z

Added Later:
Well of course I started to think about this and wondered how I might do this on windows and I came up with this basic example:

#!/usr/bin/perl -w

use strict;

use Socket;
use IO::Select;
use IO::Socket;

my $select = IO::Select->new();

while(<DATA>)
{
  chomp;

  if ( my $server = IO::Socket::INET->new(LocalPort => $_,    
                                          Listen    => 10,
                                          ReuseAddr => 1) )
  {
     $select->add($server);
  }
}


while(1)
{
    foreach my $ready ($select->can_read(1))
    {
       my $client = $ready->accept();
       print inet_ntoa($client->peeraddr()),
             "  ",$client->sockport(),"\n";
    }
}
__DATA__
2048
2049
2060
[download]

The ports that you want to monitor are the numbers after the __DATA__ . You can probably take the rest from there :)

/J\