@frescomannen: Enter http://www.giantbomb.com/podcast-xml/premium/ in for the feed URL/
Tthen go down to advance settings and enter your username and password under "Feed Authentication"
This worked like a charm for me and was the first result on a Google search, so thanks! The only thing I ran into is that it requires you to use your "actual" Giant Bomb username (e.g. shieldb in my case), which is different from the username I use to sign in to Giant Bomb (e.g. firstname.lastname@example.org)