Erstellt eure Form und benutzt diesen Code um die Form am unteren, rechten Rand hochfahren zu lassen.

public void Animate()
    {
        this.Location = new Point(SystemInformation.VirtualScreen.Width - this.Width, SystemInformation.VirtualScreen.Height);
        for (int i = 0; i < this.Height; i++)
        {
            this.Location = new Point(SystemInformation.VirtualScreen.Width - this.Width, SystemInformation.VirtualScreen.Height - i);
        }
    }