FreelanceStation - Time tracking and Invoicing for Mac. Built for freelancers.
timeBuzzer - timeBuzzer enables freelancers and project-driven teams to track their time at the touch of a button, understand where their time goes and create reports with just a few clicks.
Qbserve - Freelance time tracking, invoicing, and productivity improvement
TopTracker - Beautiful, free time tracking
Toggl - Toggl is an online time tracking tool. It features 1-click time tracking and helps you see where your time goes. Free and paid versions are available.
Traqq - Team time tracker with dynamic screenshots, productivity metrics, and apps & website tracking. Track hours within seconds with Traqq's simple UI and lightweight app.