Google Calendar - Spend less time managing your day & more time enjoying it
Appointment Booking Calendar - With the Appointment Booking Calendar you can accept online bookings from a set of available time-slots in the calendar.
Jorte - Schedule books must be practical and has a good design.
MakePlans - Online appointment booking - MakePlans
Business Calendar - Powerful and easy to use calendar app for Android including weather, widgets and tasks.
Dudle - Dudle is an online scheduling application, which is free and open source.