Perlmonks doesn't use web server authorization like that. It's all cgi script-based authentication based on cgi params or cookies.

# UNTESTED
use HTTP::Request;
use LWP::UserAgent;

my $ua = LWP::UserAgent->new;
my $req = HTTP::Request->new(POST=>'http://perlmonks.com/index.pl?op=l
+ogin;user=maddfisherman;passwd=******');
my $content = $ua->request($req)->as_string;
[download]

And if you're thinking of writing a votebot, don't. :)