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
[email protected]