Hank49:
Didn't your CD cover this during your IDC?
Anyways, and with the disclaimer that I do not keep up on how PADI's cooporate structure develops, it's roughly as follows:
PADI Worldwide is a privately held company, mostly owned by the (family of) Cronin, with some key employees (Drew Richardson, for example) also being among the (minor-share) owners.
The "regional" representations (PADI Europe, PADI UK, PADI Nordic etc.) are independant companies from PADI Worldwide, operating under an (exclusive, I think) "license" to market and develop PADI products and generate c-cards in their respective region. Some of these regional PADI's are wholely owned by PADI Worldwide (Padi UK, for example), while others are independantly owned (such as PADI Europe). The exact relationship between PADI Worldwide and the regional representations are beyond my knowledge.
What you, as a PADI member (DM or Instructor) pays for is basically the "right to generate c-cards with PADI's name on, as long as you follow PADI standards". Which implies that your membershib fees in principle goes to developing, maintaining and defending these standards (and all the follow-up things such as lobbying legislative bodies in different countries, developing teaching materials etc).
That's, in brief and probably rough terms, about it.
I'm sure that if you pick up your phone and call your local friendly member-service representative at PADI, they'll be able to give you much more (and much more accurate) details. I'd be surprised if PADI doesn't have some sort of booklet describing the cooporate structure somewhere in their arsenal, so if you call them, ask 'bout that
Hope it helps...