c# - The latest reactive extension (Rx) tutorial

I am quite interested in Reactive Extensions but I cannot find an up to date tutorial. I started with Curing the asynchronous blues with the Reactive Extensions for .NET but it is out of date. I can figure out some changes but I could not get many examples working.

I found many articles on the web, mainly from 2009,2010 but they are also incompatible with the current release. I am especially interested in using Rx with Windows Phone and WebClient:

WebClient wc = new WebClient();

var o = Observable.FromEvent<DownloadStringCompletedEventArgs>(wc, "DownloadStringCompleted").Select(newString => newString.EventArgs.Result);

// Subscribe to the observable, and set the label text
o.Subscribe(s => myLabel.Text = s);

// Start the download
wc.DownloadStringAsync(new Uri("http://www.data.com/service"));

Do not work anymore and replacing FromEvent with FromEventPattern is not enough.

Can somebody point me to an up to date resource?