application to grap some data from site

Hi , I need an application that grape data from site [login to view URL] an example is <[login to view URL]> if we changed the last number in link we get another user with his details, the final result of the project should be a list of possible id's and their data. Another level of the project is to make a registration of every id at <[login to view URL]> so we can get the whole user data from the same site. I don't know if it's legal to access that data or not. Please tell me in your bid what exactly you can offer.