The official City of London Corporation site for Broad Street Ward is a good place to start.  For some interesting historical background – http://www.british-history.ac.uk/report.aspx?compid=46755 – which shows that the Ward used to encompass additional sites of interest such as the Bank of England, the Stock Exchange, the Merchant Taylors, the Penny Post Office (and telegraph centre), as well as several churches no longer in the Ward.  Another good historical link is here – http://www.londonlives.org/static/CityLocalGovernment.jsp

The very best way to get to know the Ward is to join the Broad Street Ward Club!