The above masterful comments are just that, but since I noticed this module in the CPAN Nodelet I thought I'd mention HTML::Encoding. Apparently it helps you figure out what encoding is coming in at you, using the function mentioned above. Might even work! But I haven't used it myself. Good luck!
in reply to The unicode / utf8 struggle, part 2: regexes
HTML::Encoding helps to determine the encoding of HTML and XML/XHTML documents...
use HTML::Encoding 'encoding_from_http_message';
my $resp = LWP::UserAgent->new->get('http://www.example.org');
my $enco = encoding_from_http_message($resp);
my $utf8 = decode($enco => $resp->content);