I befriended a gentleman who instructs bondage/suspension on Fetlife and he shared this awesome link for his free tutorial! I've only done a few pages but it looks great so far and there is absolutely no obligation to buy anything or give your information... You just choose a screenname and password. Check it out:
A cursory glance at the articles offered shows a lot of important information for all levels of bondage enthusiasts (save, perhaps, the most advanced).
For example, his discussion of the location of the location of the radial nerve is an important reminder that caution is essential; damage can be done very easily without a little understanding of what one is doing.
Great find! Looking forward to reading this at greater length as time allows.