#!/usr/bin/perl -w
use strict;
use LWP::Simple;

my $url;
my $site;

print "URL to check: ";
chomp($url = <STDIN>);
$site = get($url);
if($site)
{
  print "$url is good.\n";
}

else
{
  print "$url appears to be broken.\n";
}

Sample run with output:

C:\perl>perl linkcheck.pl
URL to check: http://www.perlmonks.org
http://www.perlmonks.org is good.

C:\perl>perl linkcheck.pl
URL to check: http://www.google.com
http://www.google.com is good.

C:\perl>perl linkcheck.pl
URL to check: http://www.blahblahblah.com
http://www.blahblahblah.com appears to be broken.

C:\perl>