Wiggio is an easy way to communicate and work in groups; provides group email, text, and voice messages, host web meetings, conference calls, and chatrooms; keep a shared calendar; store/edit files; poll the group; and keep track of group tasks.
"28 tools for creating graphs, Gantt charts, diagrammers, calendars/schedulers, gauges, mapping, pivot tables, OLAP cubes, and sparklines, in Flash, Flex, Ajax or Silverlight."
Not all free, but there is a free tool from Google that wasn't too hard to use.
If you use Google tools a lot then this is a great place to go to get some tips/tricks. I learned two things about Google Calendar that I wasn't aware of: attaching Google docs to items and showing free/busy as my status.
"What is mySchoolog?
mySchoolog is an online web-based application to organize your school life easily. You can easily organize everything about your school life with mySchoolog."
"What is Soshiku?
Soshiku is a simple but powerful tool that manages your high school or college assignments. Soshiku keeps track of when your assignments are due and can even notify you via email or SMS. "
Another shot at a management tool (I personally need as many as I can get my hands on!)