I'd start by looking at what your OS' printing software can do natively before striking out on my own. For instance most Linux distros and OS X have CUPS which I'm sure has some sort of queue management.

Its the hold queue thats creating the problem - I can move jobs between queues with cups, but getting it to just hold jobs is the hard part. That feature will be in the next release.
Ted
--
"That which we persist in doing becomes easier, not that the task itself has become easier, but that our ability to perform it has improved."
  --Ralph Waldo Emerson

In case anyone is looking for a easy snippet. :-)

#!/usr/bin/perl
use warnings;
use strict;
use Net::CUPS::Printer;
use Data::Dumper;

my @printers = cupsGetPrinters ();
print "printers-> @printers\n";

my $printer = cupsGetDefault();
print "Default printer-> $printer\n";

my %options =();
my $jobid = cupsPrintFile($printer,"./$0",'Job1',\%options);
print "jobid-> $jobid\n";

my $jobs = cupsGetJobs($printer,1,0);
print "jobs-> $jobs\n";
print Dumper([$jobs]),"\n";

my $cancel = cupsCancelJob($printer, $jobid);
print "cancel-> $cancel\n";

#my $jobs = cupsGetJobs($printer,1,0); 
#print "jobs-> $jobs\n"; 
#print Dumper([$jobs]),"\n"; 

my $user = cupsUser();
print "user-> $user\n";
exit;
[download]

If I was interested in this problem, I probably would work out a way using Tk, Gtk2 or POE to keep a loop going, and build my own queue. Then runs cups on a different port, and have a custom daemon listening on port 631. The daemon can then loop, and monitor printer status, and assign jobs to the printers depending on some criteria you need.

---

I'm not really a human, but I play one on earth. flash japh