Keep track of how long a project takes, get a better sense of billable hours and find out where you are wasting time
http://www.stcassociates.com/lab/timetracker.html
I loved this tool and used to for the first couple of years as a consultant. Since then, I have moved on to OfficeTime, a more powerful tracker (which lets me have categories for multiple projects and has an invoice system built in). If you are just starting out, enjoy this free tool and when you are ready to expand, consider OfficeTime – they are inexpensive, reliable and offer great customer service.