Ledgejumper... look here <A HREF="http://search.yahoo.com/search?fr=slv1-&ei=UTF-8&p=Soes+Book" target="_new">http://search.yahoo.com/search?fr=slv1-&ei=UTF-8&p=Soes+Book</A> Also there was a guy in Richmond, Va that wrote a book called SOES Book... a little expensive but really explained how they "ECNs" worked...