getting started with a new project

1I have a real world project to do and just finished converting the data and laying it out in mySQL. Essentially what needs to happen is this:

1. User plugs in location (zip code) - that information is stored and even displayed on screen for the entire session (think yahoo yellow pages) - So anything you do thereafter is filtered on that location.

2. basic look-up - user then is free to put in a medical code or the affiliated description for that code and a look-up/search is performed on that information with respect to the location (i.e.: miles from)

Essentially just a simple search page right now with the added complexity of a stored location. I have about 6 tables although I believe only one or two will be used for this initial screen. Can anyone help me get started here?

What does the code look like to enter in a zip code, do a quick search to validate the location and maybe return/display the actually town (I have the data) more importantly STORE that location to be used for all look-ups? Would this be in the controller with a corresponding view of just this piece?

What does the code look like to build a basic look-up and return results to the same screen? Controller?

Any help is appreciated - just want to make sure I am starting this thing out correctly using the 'rails way'