web crawling 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...

Hey, you will probably want to use PHPs CURL functions to achieve this:
http://uk.php.net/curl

good luck!

Kinda depends on the specifics, but you'll probably want to get the file_get_contents function:

http://us2.php.net/file_get_contents

That will allow you to read the contents of a URL into a string. From there you'll have to parse the data you need out of the HTML.

HTH,
Mubs

well not long ago i made a script that scans through a site and checks if every link works, im sure you can use the same method here... you use file_get_contents or i think you should be able to to use http://us2.php.net/manual/en/function.fread.php then just make it look for similarities eg..

then just do strpos($mystring, "<td>");
then loop it ect..

or you could make a reg. ex.

or if the website header neaver changes then i suppose you could read from a line.

anyway theres a few little hinters