PHP coding

Description: Need a php script that will search a website that the user enters (may require you to login to view the page) and then search that page for a string that the user inputs, it needs to check the page every 60 minutes to see if it contains the string, if it doesn't have the string it needs to get logged into a database, the user needs to access the database but only theirs, as im anticipating multiple users

Additional

Would be great if you could add a login page, and allow me to control these things, kinda like an admin panel

1. How many websites one person can search
2. How long they can track for, e.g. one day, one week
3. How long between searches, like how long before it checks if the string is there again

Please either post or pm me your quotes, you can also leave a comment in the code saying who designed it as i wont remove it