Assistive technologies that were originally developed for people with visual and learning differences can help anyone with their coursework and assignments. These tools are all free, some are for PC, some for MAC, some for both.
Options that work on both a MAC and a PC:
Use the text-to-speech feature in your MAC.
To "speak" text, select the text in any MAC program (Adobe Reader does not work, use Preview for PDF files) and then press the key combination you selected. To stop reading, press the combination again.
Adobe reader X has text-to-speech and magnification capabilities. Remember however this is dependent on the PDF file being accessible and having the underlying OCR and tagging that makes it more than just an image file.