A note for all of you freelancers like myself.

I have to recommend you a wonderful time tracking and project management web-based application. It's called Intervals
We use it at my company to track our time, manage our projects, tasks, to upload documents that can be viewed by our clients and by the rest of the team around the world, etc.
Also the system keeps track of the budgets, generates reports and invoices for the clients. It really makes our work-life so much easier.
Personally, keeping track of time is the hardest thing, but intervals has little timers that your run while you work on your tasks, and for the multitaskers, you can have various timers going at once.
You can try it for free http://myintervals.com/php