smart notebook and audio files
Once you've made your audio files in Audacity or another recording program they can be attached to objects in SMART Notebook. Then when students click on the image or text they can hear it read. The video above has more specific information on how to attach audio files.
EdWeb.net is a social network for the education community. Over the past 14 months I have been following one on ebooks that has provided very interesting information about the many different formats and what other schools and libraries are using.