ActiveCollab is a project management and collaboration tool that you can set up on your own website. Have an area where you can collaborate with your team, clients and contractors and keep projects on track while retaining full control over access permissions and your data.

Keep Projects on Track.Plan your projects and track their progress... activeCollab lets you assign tasks to people, define what is urgent. See what your team is doing and what they need to do, discuss stuff that you are working on and more.
Collaborate.Communicate with your team, clients, suppliers and everyone else you are working with in a friendly and an easy to use environment. Discuss and comment, receive email notifications, stay in touch. Everything is saved and available for future reference.

Take Control.Install activeCollab on your own server and keep complete control over your data. With a little bit of CSS magic you can completely change the look and feel of your activeCollab installation and make it match your website and visual identity.
Extend and Integrate.If you have special needs you will love activeCollab. Use plugins to extend the system and make it work exactly how you want it to. Feel free to integrate activeCollab with other tools and services through an API.

Demo : http://www.activecollab.com/trial/