NaturalReader is a downloadable text-to-speech desktop software with natural-sounding voices that can read to you any text such as Microsoft Word files, webpages, PDF files, and E-mails.
Free and premium versions are available.
Read&Write is a toolbar that sits atop the screen so that text from various applications can be read aloud. A free 30 day trial of the program is available. Once the 30 days have elapsed, the premium features will be deactivated but the text to speech function will continue to work.