Our number formatting is in US. You can change in the code to suit your specific needs. Here is the PHP manual on number_format
http://us3.php.net/number_format
I will use an example here from showproduct.php
if ( !empty($currency ) ) $askprice = "{$csymbol}" . number_format( $askprice, 2 );
for say french you would change to this
if ( !empty($currency ) ) $askprice = "{$csymbol}" . number_format( $askprice, 2, ',', ' ');