use strict;
use warnings;
use LWP::UserAgent;

print 'Enter Search: ';
chomp( my $x = <STDIN> );

# Create a user agent object
my $ua = new LWP::UserAgent;
$ua->agent("AgentName/0.1 " . $ua->agent);

# Create a request
my $req = new HTTP::Request POST => 'http://www.usps.com/cgi-bin/zip4/ctystzip2';
$req->content_type('application/x-www-form-urlencoded');
$req->content('ctystzip='.$x);

my $res = $ua->request($req);
my @matches;

my $data = $res->content;
$data =~ /----------</g;
if ($x =~ /^\s*\d{5}\s*/) {
    while ($data =~ /\G(br>((\w+\s)+\s*\w\w ))/ig) {
	push @matches, $2;
    }
} else {
    while ($data =~ /\G(br>(\d{5}))/ig) {
	push @matches, $2;
    }
}

print 'Found ',$#matches+1,' matches:',"\n  ", join("\n  ", @matches),"\n";

##</code><code>##

[duelafn@XYZZY bbdb]$ perl States.pl
Enter Search: Mishawaka, IN
Found 0 matches:
  
[duelafn@XYZZY bbdb]$ perl States.pl
Enter Search: Chicago, IL
Found 0 matches:
  
[duelafn@XYZZY bbdb]$ perl States.pl
Enter Search: 84102
Found 1 matches:
  SALT LAKE CITY             UT 

[duelafn@XYZZY bbdb]$ perl States.pl
Enter Search: 12345
Found 1 matches:
  SCHENECTADY                NY