ResourceGuru - The fast, simple way to schedule people, equipment, and other resources online.

Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.

Float - The leading resource management software for agencies, studios, and firms. With a simple, drag and drop interface and powerful editing tools, Float saves you time and keeps projects on track.

Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.

When I Work - When I Work is an employee scheduling and communication app using the web, mobile apps, text messaging, social media, and email.

EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.