如何在magento中启动一个功能

I would like to set up a zip locator functionnality straight from the home page of a pizza magento website. The idea is to redirect user depending on his postcode to a specific store (I set up multistore option in the backend, each store match a real physical store) so he can be deliver (or not) by the nearest pizza shop.

The idea is pretty much simple but i didn't find any good ressources abording the subject...So if you have good link/tutorial/how to, or know the basic step to build it from scratch..like builiding a plugin or surcharge precise core lib..

Thx

Have a look on store restriction extension. It is the same way you have to follow, you check a parameter ( a session or a zip code) and redirect the customer to the right store.