Blogger, the firm that provides the service for this blog, has just announced a new version of their system which makes it usable for an internal school blog.
In addition to a number of nice usability upgrades, Blogger is making it possible to limit access to the blog. So, for example, you could make it so that only teachers or students can access your site. Adding allowed viewers is as easy as uploading the email addresses for everyone you want to be allowed in. Certainly worth a look.
The new features are for new accounts, for now. People with current accounts have to wait for the features to be rolled out.
Making a private blog