Your doubt stings. I realized that XML::LibXML will now do URI fetching itself so we can leave out dealing with the user agent stuff.

#!/usr/bin/env perl
use strict;
use warnings;
use URI::Amazon::APA;
use XML::LibXML;
use XML::LibXML::XPathContext;

my $key = $ENV{AWS_KEY} || "YOURKEYHERE";
my $secret = $ENV{AWS_SECRET} || "youforgottoputyourownsecretin";
my $asscociate = $ENV{AWS_ASSOC} || "this-isnt-it-20";

my $title = shift || die "You must provide a search string";
my $mode = shift || die "You must provide a mode, e.g., Books";

my $uri = URI::Amazon::APA->new("http://ecs.amazonaws.com/onca/xml");

$uri->query_form(
                 Service       => "AWSECommerceService",
                 Operation     => "ItemSearch",
                 ResponseGroup => "Large",
                 AssociateTag  => $asscociate,
                 Title         => $title,
                 SearchIndex   => $mode,
                );

$uri->sign( key => $key,
            secret => $secret );

my $doc = XML::LibXML->load_xml( location => $uri );
my $xc = XML::LibXML::XPathContext->new($doc);
$xc->registerNs('amzn', $doc->getDocumentElement->namespaceURI);

if ( my @error = $xc->findnodes('//amzn:Error') )
{
    die join("\n", map { $_->textContent } @error ), $/;
}

for my $item ( $xc->findnodes('//amzn:ItemAttributes/amzn:Title/text()
+') )
{
    print $item->nodeValue, $/;
}

# print $doc->serialize(1);
[download]

Set-up ENV or add your info to the script and then–

node-934250.pl perl Books
Learning Perl
Programming Perl (3rd Edition)
Learning Perl, 5th Edition
Perl Cookbook, Second Edition
Perl Pocket Reference
Regular Expression Pocket Reference: Regular Expressions for Perl, Rub
+y, PHP, Python, C, Java and .NET (Pocket Reference (O'Reilly))
Intermediate Perl
Modern Perl
Beginning Perl for Bioinformatics
Automating System Administration with Perl: Tools to Make You More Eff
+icient
[download]