DSpeech is a program with the option of saving the output to many different formats, great for creating audio books from text sources. It also supports changing the characteristics of the listeners e.g. insert contrasts, highlight certain words, spell them out etc. using tags.
The app works out-of-the-box on WinXP and above, with the included Microsoft search engine SAPI5. For WinNT/2K, you’ll need to set up the speech engine. You’ll see links for voice collections and plugins, speech engines on the program website.
The application can import text from PDF, DOC, DOCX, RTF, HTML, XML and TXT and output to OPUS, OGG, AAC, WMA, MP3 and AMR.