how to post form data from asp.net page to another url?

If I'm interpreting your rather vague question correctly, you want to enter a phone number in a form, then have the form POST to another website that returns a postal code based on the phone number. If you know of a service that provides that function, and plan to use it, you probably will find the information here[^] quite useful.If you don't know of such a service, you'll need to write it yourself, in which case you don't need to worry about redirection.

By the way, if you enter a phone number in a Google search, it will quite often return the address associated with the phone. It doesn't work as well as it used to, now that so many morons are cluttering up cyberspace with paid-for phone lookup services, but sometimes you get lucky.