Has anyone tinkered much with http://www.talkr.com ? Just found it in a search for interesting podcasts. I took the couple minutes register, and the next thing I know...I was listening to posts from kairosnews.org being read to me in a quite pleasant voice. I was actually pretty impressed by the intonation skills the synthesizer had. Anyway, here's the site's claim from its blog:

"Our pitch is simple: we will convert your text-only blog into a podcast for free. We will monitor your blog every hour, and convert each new article into an mp3 audio file using the best speech synthesis software on the market. We will host those audio files and provide you with an RSS feed (and bandwidth) to make it easy for your readers to get access to your podcast."