Mumble - Mumble is an open source, low-latency, high quality voice chat software primarily intended for use...
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
Discord - Step up your game with a modern voice & text chat app. Crystal clear voice, multiple server and channel support, mobile apps, and more.
Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.
GSC - With GSC, you can pick from any of 14 worldwide datacenters to host your own free voice server.
Strikethru - Strikethru is a kind of to-do list notebook for managing work lists and staying updated with the important tasks.