use LWP;

for (...) {
    my $pid = fork();  die "couldn't fork" unless defined $pid;
    unless ($pid) {
        my $ua = LWP::UserAgent->new();
        
        my $response = $ua->get('http://...');
        ...
        
        exit;

    } else {
        select undef, undef, undef, 0.25;
        kill 15, $pid;
    }
}