Pulse 24/7 - Booking & scheduling mobile app for service providers
Appointment Booking Calendar - With the Appointment Booking Calendar you can accept online bookings from a set of available time-slots in the calendar.
MakePlans - Online appointment booking - MakePlans
Dudle - Dudle is an online scheduling application, which is free and open source.
PHP GZ Appointment Scheduling Script - PHP GZ Appointment Scheduling Script Web based scheduling software that runs on your web site.
Launch27 - Online booking & appointment scheduling.