gistfile1.cs

//Need http://nuget.org/packages/Microsoft.Bcl.Async

internal static class WebRequestExtensions
{
    internal static Task<WebResponse> GetResponseAsync(this WebRequest request, TimeSpan timeout)
    {
        var asyncTask = Task.Factory.FromAsync<WebResponse>(request.BeginGetResponse, request.EndGetResponse, null);
        var timeoutTask = TaskEx.Delay(timeout);

        return TaskEx.WhenAny(asyncTask, timeoutTask)
            .ContinueWith<WebResponse>(t=>
            {
                if (t == timeoutTask)
                {
                    asyncTask.ContinueWith(t1=>Trace.WriteLine(t1.Exception.ToString())); // Observe exception if request fails
                    throw new TimeoutException();
                }

                return ((Task<WebResponse>)t).Result;
            });
    }
}