ASP 2.0: searching for items in other profiles

[Ya Ya]

I am using the Profile feature in Asp.net 2.0

For each user, I store several items and one of them in the phone number.

When the user fills his phone number on the form, I would like to check if
another user stores the same phone number.

How do I search the profiles of other users?

Thanks

Ra***@hotmail.com