I want to send some information that will be received directly by the
offices of Def Jam president, Jay-Z aka Shawn Carter.  I need a
mailing address and would like to know the appropriate protocol to
ensure that the information will at least get in the hands of Jay-Z's
adminstrative assistant, etc.  Basically, I don't want to send info.
that's just going to be thrown in a "slush pile" with a bunch of demo
tapes because I'm not trying to get a record deal.  The info. I'm
sending is not music and not music-related; but more like a business
proposal.

Looks like if you try a free 14-day trial at IMDB.com you can have
access to his contact information. 
http://pro.imdb.com/name/nm0419650/

I haven't tried it out becuase I don't want a subscription so it may not have it.

I am an IMDb Pro subscriber. The contact info for Jay-Z given by IMDb
Pro is rather scanty: they just list the Def Jam URL.