Converts from Microsoft PowerPoint (
.PPT extension) to Macromedia Flash (
.SWF extension) using OpenOffice
There are a huge number of commercial products that do this (in case you didn't notice the the Google Ads at the top of the page). I haven't tried any of them, but they all say they have more bells and whistles than mine.
MasterNewMedia also has an exhaustive list of PowerPoint conversion tools, with additional ones in the comments.