getting suffix for symbols

Hi

I am using getSymbols and want to try and find somewhere I can look up 
the exchange suffix for a symbol.

eg I know Westpac is WBC.AX with the AX being the Australian Stock 
Exchange but I have an EFT called GLD which is on the NYSE Arca (I 
think).  I have bo idea what the suffix is.

Is there some central reference for these suffixes.  If not does anyone 
know what the right one is for this symbol to get the data down using 
getSymbols.

Thanks.

Stephen