PaulMC,
I think you need VBA to do this. Maybe go to: http://skp.mvps.org
In the VBA section there is a sample on how to split up a PPT presentations
into individual slides.
Luc Sanders
MVP - PowerPoint
What do you mean with "attach to a SharePoint site"? In SharePoint, you can
have a slide library. You simply upload a presentation to this and it
automatically separates the slides so that they can be re-used separately in
other presentations.