The Presidential Transition website has loads of information about how the transition works and what positions the president can fill.
Here is the main page for the Leadership Positions. And for anyone who has been in Washington for more than 2 days, here is the all-powerful Plum Book.
For a bit more information on what these powerful people are supposed to do, Brookings has the Prune Book.
Loads of good information for background stories.
Or to start a pool as to who gets what positions in the new adminsitration.