I am using MS 2007 on my new computer and have used Producer for 2007 but
when I went to open it using my other computer (running MS 2003 and Producer
2003) it will not work. Is there a way to sdave the file or anything so that
it can be opened with 2003?

Have you tried to install Producer 2007 onto your machine running PPT 2003.
This web site says it will work:
http://blogs.msdn.com/powerpoint/archive/2008/06/06/the-return-of-producer-for-powerpoint.aspx

This new version of Producer supports PowerPoint 2007 and earlier versions
of PowerPoint.  This is a compatibility upgrade and there are not any new
features.

As an aside to my previous post, the beta for this product has been extended
until the end of December 2010 and if you have a previously downloaded
version prior that was to expire earlier I would recommend downloading and
installing the latest build.