If you are looking for a quick and easy way to know how much time you spend on various activities, to later bill your clients for it, then you need ActiTime.ActiTime is a web-based time control and registry system, that`s independent and totally free. You can access it via any web browser, even by various users (for example, employees of a company) at the same time. Thus you can know how much time each of these people uses on each task or project.The ActiTime system has support for configurable reports, so you can analyze the registered information easily. To download it you need to register on the author`s web, but it is completely free and quick. You just have to give a name and an email address.