Back when the original iPhone was released, in June 2007, one of the most-frequent complaints was that it didn't include a program for keeping track of tasks and to-dos. We noted this omission ourselves in our article on features we'd like to see.

We're still waiting for iCal's to-do lists to find their way onto the iPhone. But the good news is that with the release of the iPhone 2.0 software and the App Store, third-party vendors can (partially) fill that void. And a quick stroll through the list of productivity apps in the App Store shows you how many developers have stepped up to the plate: earlier this week I found 13 to-do-list programs; five more-advanced task managers designed around the Getting Things Done (GTD) system or aimed at complex project management; seven apps focused on keeping shopping lists; and a handful of apps, such as Jott, that use voice-recording and other unique approaches to help you remember the myriad tasks you need to complete in your busy life.

I decided to focus on the first group--basic list managers--as I suspect that most iPhone owners will be more than satisfied by a simple app for tracking lists of to-dos. (We'll be covering the other types of apps in future reviews.) Specifically, I looked at Chores, Dobot Todos, Lists, Lists (yes, two apps with the exact same name), My Lists, myTo-Dos with email, Tanjas Checklist, Tasks, and To Do.

As I did with Sudoku, I choose a few of the better options to cover here. None of them offers all the features I'd like to see in a simple to-do-list app, but each has unique attributes that merit your atttention.

List limitations

Before I get to my impressions, I should point out a couple major caveats that apply to most to-do and task-management programs available for the iPhone. First, none take advantage of Leopard's Calendar Store technology, which means none sync directly with your to-do lists on your Mac--in iCal or in Mail. And although some we'll be covering later do sync with online services, none of those services sync directly with OS X. In other words, there are currently no to-do-list apps that can sync with your existing to-do lists in iCal or Mail.

Second, unless a particular app is a client for an online service and can back up your tasks online, or has a Mac OS X version that can sync with the iPhone, all your to-do data is stored on the iPhone, within the app itself. So if you ever delete the app from the phone, your to-do lists are deleted, as well. (Similarly, if your phone ever has a problem that requires you to restore it, and iTunes is unable to restore your data from its backup--something that's happened to me numerous times--that data is gone for good.)

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