In managing a group, maintaining frequent communication while keeping group information organized is essential for a successful project. While you can spend hundreds of dollars on tools that are excessive, not applicable and just a hassle altogether, you can do what I do and go cheap and easy with the following free tools.
Google Docs- With the ability to share any Word, Excel, or Power Point (technically those are Microsoft's but you get the point) document online with multiple users able to view and modify the documents updated in real time is simply cool. Gdocs provides a solution to those annoying meet up times where half the members are late, and the other half contribute nothing. With the Gdocs you can view who and when other users are making edits, have viewed, or done nothing to the document- no more free loaders.
Google Calendar- Do not worry. I am not going to keep explaining how awesome Google is, but this tool is important so show patience. Google Calendar has a similar interface as an Outlook, or any other calendar you use, but now you can separate your schedule to view different categories such as work, home, or fun (or whatever you want to name it) so you can view schedules specific to your categories. Additionally, you have the ability to share your calendar with others making it that much easier dismiss how busy they are.
Dropbox- Giving 2G of free space to new users, Dropbox allows you to access and share files with multiple users on the web across any device synced to your computer, allowing for on/offline access.
Sign Up Genius- Whether your scheduling an event, or finding meeting times for your group members, signupgenius.com allows a user to create an event which members can easily enroll in based on their availability. Plus the site can manage your contacts for future sign ups, and export your sign up list to a spreadsheet offline.
Gantter- Gives you the full capabilities of having detailed Gannt diagram, online, and for free. Taking project management to the next level.
Passpack- Getting locked out of online group projects for forgetting passwords won't happen anymore. Easy way to share secured passwords with a group.