Hi all,



Is there a way and how to write code to compare prices over internet? If we

look at Buy.com or MySimon.com or qixo.com, they do price compare for the

same kind of item. Do they have a local database with all the information?

But how about get data from internet (other people's web sites) dynamically

and then show the results in a web page? 



For example, if I have money, can I build a web to find the cheapest book

prices for my web users simply by gathering and comparing prices from web

sites of Amazon.com, Books.com, etc? If possible, how? Tools? How big is

this project? Is it possible then somebody write a web page to query other

websites without asking permissions? 



Thanks a lot for helping.