You will need to convert the powerpoint to a one page document in Word.
Use Zamzar to convert from ppt to docx : http://www.zamzar.com/convert/ppt-to-docx/
Once converted , Install this to your WordPress Site
Once activated, go to Add Post , scroll to the bottom of the post and you should see:
Find your .docx document and upload it , then click insert into Editor
Trackback from your site.