My recollection is that there is a good discussion of the concept of a  
"school of economics" in Schumpeter's History of Economic Analysis.  I  
can't lay my hands on the precise location quickly, but I bet that some of  
our colleagues can.  It is somewhat consistent with the "national meaning"  
of a school developed by Szaki that Schulz referenced, expect that it is  
more grounded in a specific place. 
 
What I recall Schumpeter saying is that a "school" is a sociological  
phenomenon, and so regular exchange among members would be necessary; maybe  
a place-oriented view like this breaks down in the age of the internet.  A  
broader view, however, might be to think of a school as a strategic group,  
much as in the economics (and business) literature tied to Michael Porter. 
 
This is a great question Jim, I am very interested in learning what you  
turn up! 
 
Bruce Larson 
University of North Carolina at Asheville