Need some help from PHP developers...

Hello All PHP Developers. Let me introduce my self. I am final year student of IT. I am very much interested in programming languages, and accept chalanges. Right now i m working on my final year project, and i need some help from professional PHP Developers. I am creating a web application that when user fills the form on my web sign in page. i-e: Field are Wesite URL : email : When user submit after providing the infomation then first it searches either that domain is registered or not that user provides Website URL field.If the domain is not registered then it generates error "Your website is not registered". If the domain is registered then it searcg for the perticualar word on users website that i'll provide it. And is this possible to find how many pages are there in website that user provides ?, and can we scan all of them ? I will be thank full to you if you solve my problem. Please response me at my email address bahadur_oad@yahoo.com