Here is the link to the CRM 3.0 SCHEMA -   This is actually multiple visio docs and not the one big whopper they sent out last year on 1.2. I have this printed out and hung up in my cubie. This stuff does help.  Everyone is different, but this is how my mind comprehends the system.  I think of it like a map of physical locations.  I don't know if it is just too much tv or what.  But I need a picture to process this stuff.