web crawler in PHP?

Hello,
I am supposed to construct a page that searches in specific websites to extract information, like those sites from where you can rent a car for example. There is a form in the site where the user selects some fields (for instance departure and drop-off date), then the data are submitted to the other page that searches 2-3 sites and finds which cars are available on those dates.
I wanted to ask if there are ready scripts to do that, if not, some hints on how to start.
I am familiar with PHP forms and data extraction from mysql databases, but when you extract data from other sites, I have no clue how I can begin and deal with it...

I have never heard of any ready scripts to do such but you can use the file_get_contents. Simply put in the url as the file.

Please search before posting. By doing so I came up with an interesting link on data mining with PHP.

This is done through PHP CURL, and a lot of programming.

http://www.addedworth.com/php/index.php?t=PHP_CURL

It's retrieve file, index content into MySQL, perform search, etc.

The other way is to visit:
http://www.hotscripts.com/PHP/Script...ing/index.html

And get all the ready made ones.
Cheers,
Spin