1) Store the values as session variables. This is the easiest way to have them available on latter pages.
2) Do you have Dreamweaver CS3 or higher? Do you have validation toolkit?
With CS3 you can use spry validations to easily add phone number validation. If you don't have that it is also easy to add with validation toolkit. If you don't have either, you would need to identify a script you want to use to do the validation.