I found this way works the best for getting me the total hours worked in a week by pay period:

Go to the Reports menu.
Click Jobs, Time & Mileage, then select Time by Name.
Set the date range.
Under Columns, I chose "week".

I then hit the collapse rows button to only see the totals. (We have project data in there, you may not need to do this step.) 
Click Refresh.

I have this set up as a memorized report and it's pretty quick. Hope that helps!