Within Teamwork Projects, you can view the time logged against your tasks by hovering over the time icon to the right of the task name.
If you hover over the clock icon, you will see a preview of the total time logged as well as a note of how much is marked as billable time:
You can also click the 'Time Logged' link in the pop up window to go directly to the 'Time Logs' list on the task details screen. Here, you can see the full details of all the logged time on that task.
For more information, see: Logging time on tasks