Well it looks like I may get some help in figuring out the Excel Encryption Algorithm. I received an e-mail from someone at a company called Arizan, looking for information on the Algorithm.
  I checked out Arizan's web site, and found they provide a way to read and interact with popular file formats on your PDA, including MS Word/Excel/PPT.
  I assume they want info on the algorithm so they can add the ability to open password protected Excel files if the password is supplied.
  I will cooperate with them, and ask that any information they discover be turned over to the Open Source community.
  I hope that with a company investing some time in this, more information on the algorithm can be uncovered.