Podcastomatic.com is a free service that automatically converts your blog posts into podcasts. The service does not require any registration on your part. To turn your blog posts into podcasts through Podcastomatic just enter your blog's URL and press "Go." Podcastomatic will then convert the text of your posts into podcasts. You can listen to the podcasts online, through iTunes, and or download each podcast.
I tried Podcastomatic this morning. It didn't work perfectly on my first try, but it did work on the second try. The voice of the podcast is very robotic and clear. Podcastomatic will create ten entries on your first use.
Applications for Education
If you need a simple text to voice tool to make content of your classroom blog accessible to more people, Podcastomatic might be the tool for you.