WhyQ - WhyQ is an appointment scheduling solution that enhances and simplifies the way companies manage the influx of their customers.
MakePlans - Online appointment booking - MakePlans
Acuity Scheduling - Automate your client bookings, cancellations, reminders & payments using the worlds friendliest online scheduling software.
Appointment Booking Calendar - With the Appointment Booking Calendar you can accept online bookings from a set of available time-slots in the calendar.
Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.
Dudle - Dudle is an online scheduling application, which is free and open source.