Appointment Booking Calendar - With the Appointment Booking Calendar you can accept online bookings from a set of available time-slots in the calendar.
Google Calendar - Spend less time managing your day & more time enjoying it
Dudle - Dudle is an online scheduling application, which is free and open source.
CalenGoo - Features | 1.0.175 for Android™
MakePlans - Online appointment booking - MakePlans
Jorte - Schedule books must be practical and has a good design.