AudioPal is a free service that anyone can use to create short audio messages to embed into blog posts. AudioPal offers three way to create messages. You can record using the microphone connected to your computer. You can record by calling AudioPal's phone system. Or you can create a message by using AudioPal's text-to-speech function. In the video that is embedded below I demonstrate how to use AudioPal's text-to-speech function and how to embed your messages into your blog.
Applications for Education
AudioPal could be a good tool to use when you want students to create messages for an audio blog. I've used services like AudioPal to have students record and share short reflections on things that they learned during the school week.
AudioPal does require that you enter an email address in order to access the embed code and sharing links. If you're students don't have email accounts, you could set-up a classroom Gmail account (something like email@example.com) that all students enter. All of the AudioPal messages that your students create would then go to that one email account that you manage.