PHP site to search if updates were made to a page, with admin backend.

I am looking to have a multi-user website created to where I can input a link (for example [login to view URL]). Under each user account created I will want the script to curl (for example) [login to view URL] and save the title tags and page size into a database. I would like to be able to set up the script to be able to check that url at various times of the day to see if the title or file size has changed. If it has changed I would like it to send me an Email and alert me. Otherwise let the timer reset until the next time. I would need the user registration script, the script for the user to input their website links, and options, and an admin back end. I can go more into detail once we agree on the project.