When I run my Blogging training days, we usually focus on getting an account with WordPress or Edublogs. Both run off the same backend, but Edublogs is tailored more for educators.
If you are interested in finding out about all the different platforms that are available, then Dodie Ainslie has put together a great overview of the various options.
You can find it here: http://djainslietech.wikispaces.com/Blogging+Platforms
Take a look at the Smartboard resource pages too – some good links there.
If you do go with WordPress or Edublogs – then there’s a guide I have written here that should help you get started, and a presentation about blogging in schools.
