Principle #1 of Universal Design for Learning is,
"To support recognition learning, provide multiple, flexible methods of presentation."
Teaching Every Student in the Digital Age: Universal Design for Learning by David H. Rose & Anne Meyer (2002)
Here are a couple of free software applications that will allow the user to provide some of those "flexible methods of presentation" in the are of reading.
ReadPlease 2003 is a simple application that lets the user open or paste text into its main window and have the text spoken aloud to the student. There are a number of voices from which to choose, you can vary the rate of speech, change the font size, and even translate the text into different languages!
UltraHal is my personal fav in free text-to-speech applications. It runs in a full-sized window, will speak items copied onto the clipboard from any application, speak instant messages, as well as allows the user to copy or open text files in its main window to be spoken. My all-time favorite feature of this software is that it will convert text into .wav files.
This means that a teacher could copy a passage from Edgar Allen Poe's "A Cask of Amontillado" (which can be found at Project Gutenberg) and paste it into either application to be read aloud. If this passage were pasted into UltraHal, the teacher could convert it to a .wav file which could be burned to CD and listened to at home. (You could actually go a step further and open that .wav file in Audacity, save it to MP3, and download it into your portable media player, too.)
Now your students with reading difficulties or who are auditory learners can have their text in visual and auditory formats.
Voila! Universal Design for Learning. For free!