i have made all my web scrappers in php
i basicly make them to mirror a websites content, ie i want to get good content on a hoilday website i own, so i extract the information from one already established site and add it to mine
i bascily use curl in php, just running from a local host server
the process is simple really
stage one extract the links from the page(s) you want
run threw the pages extracting the infomartion required, at this point either save it or post it to your site - in your case it would be simply saved for offline use
theres nothing complex about it, just time comsumming