We swear by Redmine.

It is an amazing open source project management tool written in Ruby on Rails.   In most small business, we find that many times there is a lack of proper communications, task scheduling and execution, and also poor workflows.   Although best suited for software development type projects, Redmine can be implemented as an organizational tool that will assist in streamlining the interaction between employees with the common goal of task completion.  You can configure users and groups and assign them to created projects. It has an amazing time tracking and ticketing system that allows large tasks to be broken down into the smallest possible task for completion.  For software development projects, it is quite easy to integrate SVN/GIT and other code management systems that can be managed directly from Redmine.  There are many reports to ensure that project goals are monitored and deadlines can more easily be adhered to and functionality can be enhanced by installing contributed plugin modules.

In many cases we use Redmine in small to medium size companies that have little to no infrastructure, creating a collaboration tool that will help push things to the next level.   The best thing of all is that this is completely open source software so you can customize it as you see fit and contribute to the project.  You can also donate to the project to help to keep it going. 

More information can be found at http://www.redmine.org

We can assist you in setting up Redmine servers so feel free to ask us about this.