There are links to several different explanations that describe how to do the
job manually (which can be complex). There are also links to Shyam's tool that
automates the process, so yes, you can buy a tool to do it but you don't have
to.
Actually some 3rd party tool can do this job easily. For example, have a
free trial copy of PPT2Flash
(http://www.sameshow.com/download/ppt2flash-download.html), just use the
"Insert Flash" shortcut feature within PowerPoint without purchasing. It's
really great way and totally free to do so.