Quote from ArchAngel:
Index quotes from the source don't have volume.
Are you talking about them constantly doing a summation of the individual volumes of all 500 stocks in the SPX and the 100 stocks in the NDX?
Haven't seen any provider do that - you can get total NYSE and total Nasdaq volume though usually.
Quote from H2O:
Create a spreadsheet, and calculate for yourself using a DDE connection.
QCharts and eSignal both provide a DDE link to excel.