Lumina (with sync)
Open iTunes to buy and download apps.
Lumina is the iPhone counterpart of the most used time tracking tool for the desktop.
Lumina is focused to show you a simple way to track your time.
The concept of Lumina is based on three columns.
Projects: A project is a bundle of tasks
Tasks: A tasks is a bundle of durations
Durations: A duration is the smallest brick to calculate your total time
For more productivity, Lumina has also a desktop application and you can sync your times between multiple iPhones and Macs via the Lumina Cloud.