Microsoft Office OneNote is now available for iPhone as well.It can also be installed on your iPad

The OneNote applicaton is available free on iTunes.com but is limited to US users only.

Steps To Maintain To-Do Lists with OneNote :

Step 1. Go to office.live.com and sign-up for Office web apps with your Windows Live ID. If you already have an Office Live account, simply sign-in.

Step 2. Open OneNote on your desktop and either create a new notebook for keeping your To-Do lists or simply use an existing notebook. Choose File –> Share –> Web so that you can access that notebook from anywhere on the web.

Step 3. Now that our environment is set-up, let’s create a task-list in OneNote. You can go this in two ways.

• Click that little drop-down near New Page and choose Page Templates –> Planners –> Simple To Do List.
• Alternatively, just start writing anywhere on the current page and press “Ctrl + 1” to convert it into a task or a to-do item.

Step 4. Next launch the OneNote app on your iPhone /iPad, sign-in with your Windows Live ID and it will download your pending tasks list that you created on the desktop. Here you can add new tasks, edit existing one or mark them as complete.
Once you have made the changes, tap the Settings icon and choose Sync. Within minutes, these changes should be reflected in the OneNote notebook that’s on your desktop.
The first version of OneNote app offers basic features and doesn’t support rich formatting. You may have obviously come across much better task managers for the iPhone but the one big advantage with OneNote is that you don’t need to run any another app on your desktop to sync your tasks with the cloud.