Data extraction from online directories

We are looking for a code to extract meaningful information (addresses, mobile numbers etc.) from some of the leading online business directories (mainly Indian but global too), and store it in Excel / Access etc. some names that come to mind are tradeindia, indiamart etc. We could start with these and then expand to others.? I am assuming code will be a little bit different for each site. Please let me know if you need more details.