tracking work hours; app recommendations for iOS/OS X?

Hey folks,

I run my own business, and i'm wanting to track my own work hours. Task-wise, i'm all over the place, so i'm in search of an application that's kind of a virtual time card that allows me to easily punch in and out and tracks my total hours worked in a day/week/month. Ideally, this would be a program that works across OS X/iOS…

Does anyone have any recommendations?

Thanks a lot!