It seems to be trying to explain the C as it goes along, but I don't think I'd get it if I hadn't done C programming in the past.

But, if you've done any Java or Objective C, you can probably infer the gist of it without serious C study.

If you can write C at the level of K&R, you'll probably be fine.

Hanson's C Interfaces and Implementations is another great book that would better prepare you for this.

Do you have general programming experience?

Yep, lots of Ruby/PHP/Python/Javascript, some Java. So I can comfortably read syntax in most languages, but obviously none of the languages I've used are as low level as C.

Yeah, brush up on pointers a tad bit (just have a look at some youtube videos, honestly), if you are uncomfortable with them, and then you should be good to go.

If you understand pointers then from a cursory glance at this tutorial you should be fine.