The following is a list of sites where you can set up an educational blog for you and/or your students.

Edublogs & Learnerblogs are created for teachers by teachers. You can use Edublogs for teachers, Librarians, Educators. Learnerblogs for K-12 school students, UniBlogs for Uni & College students and ESLBlogs for students and teachers involved in English language learning. The site contains many educational features and support documents and is entirely free to educators and schools.
global classroom
Global Teacher is a joint project between the Victorian Education Channel and The School Library Association of Victoria.
The project is designed to provide teachers with a weblogging space which supports Research in the use of this new technology. In order to participate we request an outline of your plans and ideas about weblogging (They can change over time) and also than you inform your Principal or your participation.
Global Student is the student space associated with the Global Teacher project.

This page from Support Blogging contains some links to blogging hosts that are suitable for educational use.

Podbean - provides a creative Audio, Video, Blog all-in-one hosting service. Now you not only can blog in text, photo, but also in audio and video. You can also search for other podcasts using tags such as education

Classroom Blogmeister is explicitly designed with teachers and students in mind, where the teacher can evaluate, comment on, and finally publish students' blog articles in a controlled environment. Check out the conditions of use on this page. You can also find other class bloggers by searching on the right hand side of this page. You can search according to country, state or year levels. Look for classes that have lots of posts to experience an authentic example.