how can i query any information/data from another web site

Hi all

I have a problem about querying any data from another site. For example ;

there are 2 boxes at www.anysite.com. And client need to enter ID and name and clicks "SEND QUERY" button and then get response and results.

I want to do the same by sending related information to that site and get result and display the result (even may be "YES" or "NO" if the information exists there) in my page.

Hope i could tell my problem by my poor english

Thanks
...