extension development tutorials ? help?

Hi - I’ve been using long enough to know that I really need to not be so dependent on the plugins / extensions of others to solve the unique problems that some of my sites pose, and I was wondering if anyone knew of a good tutorial or book for building expression engine plugins and extensions. I’m not a natural coder, but, given enough time and some good documentation, I can usually figure things out. I’ve gone through the EE docs example, but as the comments suggest, it’s got a few errors and it’s not really too thorough. I saw a blog post on greg akers site about module development, but it is still in progress, and doesn’t discuss extensions. I think what I really need is something fairly comprehensive. Has anybody seen something that might help me get started?

Thanks