Hi Cassandra,
If you mean you want to directly convert your PowerPoint files into Little Reader files, I'd like to clarify that this type of feature is not available in Little Reader. What you can do as a workaround is to recreate the contents of your PowerPoint files in Little Reader as new Categories.
Please have a look at these support articles for further instructions on how to create your own Little Reader categories:
Editing Categories
http://support.brillkids.com/entries/20428831-editing-categoriesEditing Words
http://support.brillkids.com/entries/20428861-editing-wordsThis might not be very ideal especially if you do not have enough time to work on recreating your presentations, so a possible shortcut for you would be to take screenshots of each slide in your PowerPoint presentation, and then add the screenshots in your LR words (in the Edit Word window's "Picture Slide" tab) -- this way you'll end up with a pictures-only category. However if you'd like to make the words in your presentation appear in different fonts, colors, etc., then you need to type in the words instead of adding word "pic slides"
I hope this helps!