Nexus provides an electronic to-do list known as Tasks. You can add tasks, either by simply typing them in or by turning an email message into a task. You can set a completion date or time, and track progress as you work through the task. You can also assign tasks to others and receive notification when the task is updated or completed.
What you can do and how you do it depends on whether you access Nexus using Outlook, Entourage or the web interface.
More information about Tasks