How do I convert a .NET console application to a Winforms or WPF application

For completeness - and for other newbs like me - you also need to add:

using System.Windows.Forms;

... to the top of Program.cs

Just add a new Winform, add the following code to your Main:

    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);
    Application.Run(new Form1());

Also, be sure the [STAThread] attribute is declared above your Main function to indicate the COM threading model your Windows application will use (more about STAThread here).

Then right click your project and select properties and change the "Output type" to Windows application and you're done.

EDIT :

In VS2008 the property to change is Application type