Gantt charts are a way of keeping track of projects you’re doing so that you can manage them more effectively. More than just a list of tasks to work on, Gantt charts provide a visual component to help you see which jobs must be done consecutively or concurrently to help you stay on top of your workload.
Bright Hub has a series of useful articles on using Gantt charts:
There are computer-based tools for creating Gantt charts, such as Microsoft Project for Windows and OmniPlan for Macintosh, but they tend to be expensive. Web-based tools tend to require paid subscriptions, though some offer an option for a limited free account.
10 Free Online Project Management Tools
Project Management Tools
Tom’s Planner is a Gantt project-planning tool. The service is free if you want to manage one project, though there’s an upgrade fee if you need to work on multiple projects.
It definitely packs the most features of any free (and a few for-pay) project management tools on the Web.
In addition to the standard task lists, time tracking, and schedules, you also get features like a discussion area, the ability to upload files related to a project, email notifications, and built-in messaging. You can even keep track of projects using RSS feeds. Not bad for a free tool!