The News and Forecast channels download data packages from Nintendo servers via plain http connection.
Nowadays, it seems the news file has moved:
http://news.wapp.wii.com/ displays a Red Hat Enterprise Linux Test Page
$0000 - $003F: padding (00) $0040 - $013F: rsa encrypted sha-1 signature of rest of the file $0140 - $....: compressed data
Data compression method is still unknown. If you calculate entropy of the data, you will notice that it is definitely not encrypted. Probably it uses a modified version of propieritary Nintendo compression method described here: http://everything2.com/index.pl?node_id=1469892