Free Project Management Software

I' d recommend you Teamlab http://teamlab.com/ - a free open source platform for project management and business collaboration. It has all the necessary tools- organizing of milestones, tasks, timetracking, forums,IM.
Here's its recent overview http://www.bettertesting.co.uk/content/?p=878#comment-603

I found this great article comparing features and costs of project management softwares.
http://www.timedoctor.com/blog/2011/02/02/43-project-management-software-alternatives.
The table shows one or two applications that you can get for free.

Can you do multiple projects? I need a software that can do multiple projects. We're a small company but growing in leps and bounds!

Thanks for the info!
Since I have been using Microsoft Project Professional 2010 for a while now, I'm a fan! It's not free, but it's SUPER robust! It has great features and is easy to use too. The free stuff is also great as it can help with basic project management, but the moment you have multiple projects and teams, they fall short - as is rightly indicated. Nothing like this best project managing software to organize tasks and streamline processes and communication. Do check out its trial version when you have a moment!