Meta real estate search engine web 2.0

I would like to create a meta real estate search engine with the capability to search the entire web including major real estate sites such as [login to view URL], Zillow , Yahoo! Real Estate, Zip Realty, Trulia. The purpose is to allow users to search thousands of real estate websites from one place and get the best relevant results, and connect to the original source of information by the link. Search by USA cities, map, zip codes and other criteria. Search categories: Homes for sale, Homes for rent, Foreclosure, with options to add more if needed. Market: main market USA and option for worldwide. I’m looking for solutions that would automate all the process of data extraction from target website, and automatically checking of duplicate data and translation into files or DB. Enter property search query > should display readable format basic information will be posted such as Address, Price, # Bedrooms and Baths, with link to point directly to the advertiser's listing page on their website. Site to include PP Click advertising features with expansion capabilities and compatible with other web technologies. Example sites: [login to view URL], [login to view URL] If providing bids please include details, with ideas suggestions, scripts you would use, and provide samples of work instead of just "yes we can do" along with other terms. Prefer open source solutions with one time setup and low overheard and maintenance.