Parsing iTunes Podcast XML in C# using System.Xml

I'm trying to parse a iTunes podcast XML feed in C# and am having trouble. It successfully downloads the feed and puts it into the XmlDocument object (tested). After that, it goes to the for-each line, but never enters the loop. I have no idea why it's saying that there aren't any elements in channel/item (at least that's what I'm thinking at this time). Heres the code:

    string _returnedXMLData;
    XmlDocument _podcastXmlData = new XmlDocument();

    public List<PodcastItem> PodcastItemsList = new List<PodcastItem> ();

    _podcastXmlData.Load(@"http://ift.tt/1tVHTLI");

    string title = string.Empty;
    string subtitle = string.Empty;
    string author = string.Empty;

    foreach (XmlNode node in _podcastXmlData.SelectNodes(@"channel/item")) {
        title = node.SelectSingleNode (@"title").InnerText;
        subtitle = node.SelectSingleNode (@"itunes:subtitle").InnerText;
        author = node.SelectSingleNode (@"itunes:author").InnerText;
        PodcastItemsList.Add (new PodcastItem(title, subtitle, author));
    }
}

Thank you in advance for any assistance! It's much appreciated!

Kirkland