You can also try Manymoon, it's free:

http://www.manymoon.com

With Manymoon you can:
* Managed private and shared To Do Lists and Projects.
* Works with clients, co-workers and partners...anyone with an email address!
* Upload documents and add them to tasks and projects.
* Integrate with Google Docs and Google Calendar.
* Twitter-like feature to let people know what you are working on.
* Automatically convert emails into tasks.