Here’s a basic intro that Michael made – for low level students really (link: pdf stored in google drive).
GCF LearnFree don’t have an intro to blogger, but they do have a great section talking about blogs in general, and an intro to Tumblr instead. Tumblr is much more visual than blogger, which can be text-heavy.
Google themselves have a fairly decent help section.
Grovo has a few videos showing the basics, including this overview. But they’re a commercial mob, and they’ll want you to pay for more.
What good resources have you found so far?