I just signed up with
Tungle.me and I absolutely love it. I know some people use genbook, but I wasn't thrilled with having to type out my services and rates to use it.
Tungle.me can sync with your google calendar, your outlook calendar and many others and looks much more professional. You can even choose blocks of time that your client or PC can choose from to schedule time with you.
I just sent a link to a PC that I'm meeting with this week, so I'll let you know what she thinks.