iOS: You won't find a shortage of task timers for iPhone in the iTunes App Store. But 30/30 not only looks great, it also works well at organising your tasks into small chunks so you actually get things done.
The app seems to get its name from the 30/30 work cycle that assumes you're most efficient when you work for 30 minutes and then take a break. That said, you can adjust the length of time for tasks up to three hours. What sets 30/30 apart from every other task timer out there is it's great look and feel.
The app uses gestures to control and create new tasks. The bright colours and clean icons make it easy on the eyes. That shouldn't really matter with a task timer, but the fact that it's actually fun to use makes it easier to, well, actually use. You can try it for yourself free of charge in the iTunes App Store.
30/30 [iTunes App Store]