Do you mean Powerpoint 2000?
Where is the .pdf file & where are you going to be using the Presentation?
What you'd need to do is to ensure that the .pdf is accessible from the PC
that's runing the presentation (i.e either on the same PC, or on the same
memory stick as the presentation, or online).
Then, just create a hyperlink to the .pdf.
You'll also have to ensure that you have acrobe reader, or another .pdf
reader on the PC that you're showing the presentation on. (If you aren't
sure, then you can look at
http://portableapps.com/node/3265 - but it isn't
as easy to install as other portable apps).
When you are giving the presentation, the pdf reader should start up & open
the document.
If you don't want to use a different program (i.e. acrobat), then as far as
I know you can't - unless you:
a: Take a screen shot & embed it as an image
b: Save the Presentation as HTML & view it in a browser.
I don't think that either is ideal, though, of course, .pdf files aren't
really ideal for presetnations - so maybe you've got something very clear
that you could easily take a screenie of.