For some reason these steps didn't work for me. If anyone else is having this issue, here's what I did (it took me HOURS to figure this out! but my professor has over 100 slides per lectures so there was no way I was printing that many pages):
1. In NeoOffice, PowerPoint, etc, export the document as a PDF.
2. Open it in Preview, and hit Tools-->Rotate Right. When it asks you if you'd like to format one page or the whole document, hit "Document."
3. Click file-->print. If it isn't already expanded, hit the small arrow next to the dropdown list labeled "Printer" to see all options.
4. Switch the page orientation from letter to landscape
5. In the drop-down menu in the middle, change from "Preview" to "Layout"
6. Select the desired number of pages per sheet (six, for me)
7. Select the first option for orientation (the arrow looks like a "Z")
8. Print away!