things to look at...

- check out this link for some concept model inspiration:  http://pinterest.com/source/conceptmodel.tumblr.com/
  
-  Edward Tufte, "Envisioning Information" is the book.
These are maps, but really look at them for the variety of notation and representation...

  
I'll look for some more specific site analysis examples, but use the resources around you and look in the library as well!