Currently in order to gain access to Processing Rules, you must become certified. The logic of this is that data can be changed so Adobe wants to ensure you know what you are doing.
However, I find that this is a pointless hoop to jump through, given that
a) I've taken the test and am certified. Most of the questions on the exam have little or nothing to do with what you can actually do within Processing Rules
b) The Processing Rules are extremely limited in what they can do to begin with,