I remember someone asking for an ISBN lookup for the Great Perl Booke Exchange, and came across this script. It uses Amazon's website for the service, and I acknowledge that some may feel ethically compelled to not use this script. I found that in testing it, the parse_amazon sub doesn't exactly function as advertised; some of the page's html has been altered slightly. below is a corrected version :

sub parse_amazon {
    my ( $text, $ashash ) = @_;
    return undef if $text =~ /Books search: we were unable to find exa
+ct matches/i;
    my ( $title ) = $text =~ /^Amazon.com: buying info: (.*)$/im;
    my ( $pages ) = $text =~ m:(\d+) pages:;
    my ( $price ) = $text =~ m:<strike>\$([\d\.]+)</strike>:;
    my ( $publisher ) = $text =~ m:\n\s+([^;\n]+);[\s\n]+ISBN:isg;
    my ( $author ) = $text =~ m:\nby <a href=[^>]+>(.*?)</font>:s;
    $author =~ s/<.*?>//sg; $author =~ s/\([^\)]+\)//g; chomp $author;
    my @authors = split /\s*,\s*/,$author; $"=", "; chomp @authors;  #
+"
    return "$title\n by @authors\n $pages pages, \$$price\n $publisher
+\n" unless $ashash;
    return { title => $title, author => $authors[0], author2 => $autho
+rs[1], author3 => $authors[2],
             pages  => $pages, price => $price*$DOLLAR, publisher => $
+publisher }
}
[download]

The script will output one of two things -- formatted text :

Perl 5 Pocket Reference, 3rd Edition: Programming Tools (O'Reilly Perl
+)
 by Johan Vromans, Larry Wall, Linda Mui
 96 pages, $9.95
[download]

or a hash

(title => "Perl 5 Pocket Reference, 3rd Edition: Programming Tools",
 author1=> "Johan Vromans",
 author2=> "Larry Wall",
 author3=> "Linda Mui",
 pages  => 96,
 price  => "$9.95",
 publisher => "O'Reilly Perl")
[download]