Be careful when you use Flash/Shockwave in Powerpoint. In my experience with both PowerPoint 2000 and XP it caused a I/O error 6 when trying to open other Powerpoint files. This can be resolved using Microsoft Office Update. Before trying to embed Flash or Shockwave into Powerpoint make sure you have the latest updates and service packs for your version of PPT. You can learn more about inserting Flash into powerpoint at:
http://www.flashgeek.com/tutorials/index.htm