Looks like you might soon be able to convert your docs into presentations. I just found this function in the source code...

var isPresentation =!!0;
function SaveCopyAsPresentation() {
var docId = GetActionDocsString(actionDocID);
SaveDocContentsWithNotify(function() {
CopyDocument(docId, true, 'doc2presentation');
});
}

[Link removed as requested – Tony]

I think "Save Copy As Presentation" was available when Presentations launched but it looks like it might have been removed with the latest menu update.

(BTW, your link leads to a private document.)

I can't find a screenshot or reference to that menu item but it was definitely there before they changed the menu.

See also these strings from the original discovery of Presently:
http://googlesystem.blogspot.com/2007/02/google-presently.html

   var MSG_DOC_TO_PRESENTATION="Convert document to presentation";
   var MSG_PRESENTATION_TO_DOC="Convert presentation to document";

Tony: "Save Copy As Presentation" was added om Oct 22, 2007

here in German:
http://www.googlewatchblog.de/2007/10/22/google-docs-vom-text-zur-praesentation/

Thanks Tony. Why did they get rid of it then? Did anyone here ever use that feature? I never did.

(Oops! Would you mind getting rid of that link please Tony?)

You mean "Save Copy As Presentation"?

I did, but it was in Oct 2007. I do not remember much...

The feature wasn't very useful simply because Google converted every document page into a slide. Most documents created using Google Docs have a single page (there's no page break), so the presentations only included the beginning of the documents.