Web/Android/iOS: We've talked before about the Pomodoro technique, the productivity method where you work in short bursts with small breaks in between. Pomotodo combines this technique with a to-do list that is available on all your devices and also tracks your overall productivity.
There are plenty of Pomodoro apps available, and we've featured some of them before. What makes Pomotodo special is that it's cross platform and free. You can create a to-do list on your phone and then when you're at your computer, start the timer and cross off the item. The list is synced, although the timer isn't. Also, it defaults to the default Pomodoro time limit of 25 minutes, and that can't be changed.
Pomotodo also tracks how many tasks you complete and how much time you take to do them, and provides monthly graphs of your work. You can see your total number of "pomodoros" for any day, your daily average, your monthly growth, your best workday and your peak productivity time.