Excellent Tutorial, Dog and Pony. I have seen a number of posts on checking a remote file, so I offer this solution using LWP::Simple, hoping this is the best place to put it.

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

my $url = 'http://www.somesite.com/somefile';  
head($url) ? print "Good\n" : print "No file\n";
#or if you don't like/know about ?:
if (head($url)) {
print "Good\n";
} else {
print "No File\n";
}
[download]

Update: yes I know this is in the head function in the tutorial, I just want to stress that it can be done to anyfile not just a webpage