As Damien said in his comment, you can use UI automation, like this in a C# sample console app:

class Program
{
    static void Main(string[] args)
    {
        Automation.AddAutomationEventHandler(WindowPattern.WindowOpenedEvent, AutomationElement.RootElement, TreeScope.Subtree, (sender, e) =>
            {
                AutomationElement src = sender as AutomationElement;
                if (src != null)
                {
                    Console.WriteLine("Class : " + src.Current.ClassName);
                    Console.WriteLine("Title : " + src.Current.Name);
                    Console.WriteLine("Handle: " + src.Current.NativeWindowHandle);
                }
            });

        Console.WriteLine("Press any key to quit...");
        Console.ReadKey(true);
    }
}