Basecamp is an excellent online software package that makes project management and collaboration easy. Created by 37signals, the entire Basecamp system is accessed and managed online, so none of the software or data is actually stored on your computer. You can share the project management with your fellow freelancers or an entire company.
Basecamp helps you manage multiple projects at a time with to-do lists, file sharing, chatting, messages, calendars and time tracking. 37signals offers a trimmed-down free version, which is great for starting out, as well as monthly plans with all of the features discussed below.
Milestones & Time Tracking
Basecamp uses Milestones to keep track of important project deadlines, such as due dates for each round of designs. You can assign a milestone to a person, relate one to to-do lists and subscribe to them in iCal (on the Mac). Your Dashboard (the Basecamp home page with an overview of your projects) will show you upcoming and late milestones so it's a great way to keep track, and not miss, deadlines.
Time tracking in Basecamp allows all of the members of your group (or just you) to record hours spent on specific tasks and entire projects. You can create reports from the "time sheets" and even relate to to-do lists. Having this, along with all of the other Basecamp functions, in one place is what makes the software such a powerful tool.