Dudle - Dudle is an online scheduling application, which is free and open source.
When I Work - When I Work is an employee scheduling and communication app using the web, mobile apps, text messaging, social media, and email.
Pulse 24/7 - Booking & scheduling mobile app for service providers
Deputy - Deputy is a software for employee scheduling, time and attendance and communication management.
MakePlans - Online appointment booking - MakePlans
ResourceGuru - The fast, simple way to schedule people, equipment, and other resources online.