try google for "register form php". you'll find some.
or you could use this (it's a very basic one):
if you're using a database, make sure you have a table called userdata

as i said this is a very basic example: there's no check whether the phone-value contains only numbers, no letters. there's no check for a valid email, and there's no check whether the user allready is registered.
Greetz,
UnrealEd