Toggl looks good, I currently use myHours.com. It's free also. I was using another program but started subcontracting for someone and she used myHours. I had to switch for her and within a couple days had moved all my time tracking there. I like myHours because the companies I subcontract for can set it up to see my hours and I can do the same for my subcontractors. It's also free.
Great advice Cristina. I know the referrals I've made have made a huge impact on the people I've made them for. That was a big lesson for me. People remember you when you help them find a solution to a problem/need they have. One particular instance comes to mind. Someone contacted me to do some work for them but it wasn't something I could handle. I knew of someone I thought would work for her got the name and they contacted each other. Now I have two people who will remember me for finding them a solution to a problem they had (one needed more work and one needed some assistance).