Project Honeypot has an HTTP:BL API available to subscribed (it's free, accept donations) people/orgs. There's a basic perl package someone wrote, I'm including a copy here.

from here

The blogspam service already checks urls against the surbl, and has its own IP blacklist. The best way to support the HTTP:BL may be to add a plugin there. --Joey

package Honeypot;

use Socket qw/inet_ntoa/;

my $dns = 'dnsbl.httpbl.org';
my %types = (
0   => 'Search Engine',
1   => 'Suspicious',
2   => 'Harvester',
4   => 'Comment Spammer'
);
sub query {
my $key = shift || die 'You need a key for this, you get one at http://www.projecthoneypot.org';
my $ip = shift || do {
warn 'no IP for request in Honeypot::query().';
return;
};

my @parts = reverse split /\./, $ip;
my $lookup_name = join'.', $key, @parts, $dns;

my $answer = gethostbyname ($lookup_name);
return unless $answer;
$answer = inet_ntoa($answer);
my(undef, $days, $threat, $type) = split /\./, $answer;
my @types;
while(my($bit, $typename) = each %types) {
push @types, $typename if $bit & $type;
}
return {
days => $days,
threat => $threat,
type => join ',', @types
};

}
1;

From the page:

The usage is simple:

use Honeypot; my $key = 'XXXXXXX'; # your key my $ip = '....'; the IP you want to check my $q = Honeypot::query($key, $ip);

use Data::Dumper; print Dumper $q;

Any chance of having this as a plugin?

I could give it a go, too. Would be fun to try my hand at Perl. --simonraven