YesBookit - Booking management system for holiday rentals
MakePlans - Online appointment booking - MakePlans
iGMS - iGMS provides cloud-based software for professional hosts and property managers with tools to automate and streamline your vacation rental business.
Appointment Booking Calendar - With the Appointment Booking Calendar you can accept online bookings from a set of available time-slots in the calendar.
CiiRUS - CiiRUS is a cloud-based reservation and guest managmenet solution that provides features and functions to manage the reservations and guests.
Dudle - Dudle is an online scheduling application, which is free and open source.