Read4me

Read4Me lets your Mac do the talking. It will read text and pronounce it in a choice of voices. You can save the audio to file.

And it is very easy to start, stop and select another voice, and change the speed of reading in words per minute.
Actually it is a full text editor with spell check, printing, saving to Rich Text Format or Plain Text.
Nice for kids, great for presenters and as a media production utility.