Google Docs and Spreadsheet has just added a very cool new interface that allows you to set up folders to organize your documents. This would allow you to set up a folder for each of your projects, courses or whatever category you need to use. Go to http://docs.google.com/ and check it out.
As yet, there appears to still be no limit on how many documents you can post into your account and I ran across a posting in the Google Blog that they have acquired www.zenter.com, which will give them technology to add a PowerPoint like presentation tool to their Google Docs and Spreadsheets tools. Go to http://googleblog.blogspot.com/2007/06/more-sharing.html to read more about this. Google is planning to roll out the new tool this Summer. I hope they include a way to add a voice narration to the presentation files.