Let users report time spent on a job

Hi

I′m creating a wp-site for a taxi company. The owner want a internet-homepage but he also want a intranet solution where users can login and report their worked time and how much money they collected. Im thinking of putting the intranet in a sub-folder or a sub-domain, but the “time tracking part” is something I havent figured out yet.

Does anyone know of a good plugin for this.