Before you get to far into this project, you have to decide how accurate your results must be. I assume since it is a 9-11 appliction, you probably want the results to be as accurate as possible.

First step is to establish what maps you are going to use. Try and get maps from the county, they are typically the most positionally accurate and have the best attributes. If this fails, you have no choice but to us 3rd party maps, (TIGER, GDT, NavTech or TeleAtlas).

What ever you decide make sure the maps you are going to use for display and your proximety seaches are the same maps you geocoded with. Never mix up the data sources, this can create all kinds of problems with misplaced geocodes. (i.e Using Sagents or GDT's geocoder and placing them on NavTech cartography in MapPoint is not a good idea.)

There are several options out there that will allow you to geocode at the county level and provide the relate to the contact info in your database. The one that comes to mind is MapInfo Pro. I also know of a company that does a similar service for several counties. Their web site is www.ddti.net.

Good Luck