collect realestate data from the Internet

Hi I am trying to build the worlds largest online real estate database And I need someone to help me. My system is called [login to view URL], and real estate agencies can create an account for free. So let me know how you can help me? It could be by collecting realestate data from the internet and sending them to me so that I can send them and introductionemail on my system. But there could be many other ways. My interest is getting as many active realestate agencies in my system as possible. Let me hear your ideas and your prices (my primary target is realestate agensies from Europe)