Siri, the virtual assistant in the iPhone 4S , among other things helps to keep a todo list. Reminders for this is Apple's new app uses. Do you have another todo app, it works just dictating text using the English keyboard, but giving commands is not supported. The app Remember The Milk, however, still managed to Siri features in their app process.For this you only need your Remember The Milk account with your iPhone 4S.