Need help with a small project

This is what I need...

Maps of every state in the US, in a computerized format of some kind, with cities and ZIP codes in the correct places.

I cannot find anything like this on the net for free. They sell physical maps, but they cost a fortune. I'm going to have to make them.

I have the data. I can get maps of the states and cities anywhere. From census.gov, I have files with listings of every city, state, ZIP codes, latitude and longitude.

The problem lies in marrying the two sets of data. How can I map these ZIP codes on to a map of a state? The grid should be easy enough to set up...if I know the lat/long of the ZIP and I know the lat/long of the state, I can pinpoint its location easily. I just don't know how to apply this visually.

My first thought was a custom made program. I have done some programming on and off in the past, so I'm not worried about the equations, but I have done very little image manipulation, so I'm kind of clueless here.

Another thought might be to use Flash. By its very nature, it's easy to mix pictures with code. I have some experience with it and the language is similar to C, which I have used in the past. Plus, maybe I could employ cool things like zoom in, pan out, etc.

Any ideas? It doesn't necessarily have to look nice or be efficient. It can be a ghetto setup, as long as it gets the job done in a reasonable amount of time. Once I have the maps, the work will be basically done.

There might be something useful in this link: http://ask.slashdot.org/article.pl?sid=04/05/28/2129226&mode=thread&tid=103&tid=152&tid=185&tid=99

Lots of good stuff there. Thanks

Mapinfo and Claritas Compass do that as well as show you what people earn, buy, and what they do.

Costs money though.