Quote from JackR:
The CRB Index, as of July 12, 2005 known officially as the Reuters/Jefferies CRB Index, is a basket of commodities which is intended to provide information as to the overall direction of commodity prices in general.
I'd hunt around in whomever you get your data from and see if any of the above helps. I don't trade it myself but the NYBOT uses the symbol CR.