Out of the box? No. But there are plenty of GIS systems you can program
against. As you are doing fairly simple stuff, you might try the SharpMap
project (http://www.codeplex.com/SharpMap). You will have to create your own
overlays for the states, but it should get you started. There are other open
source implementations out there, but not sure if they are .NET.

For what you are doing, Google Maps may be a free/inexpensive option, as
well. But, you will still have to write the overlays to separate the states,
etc.

A cheaper option, for commercial software, is a component that can map using
TIGR data (from the census beaureau). They will still generally run a few
hundred to a few thousand, so this might not be an option for you.

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MapInfo.com, ESRI.com are two pretty sophisticated vendors of mapping and
geospatial products; you'll get whatever job you need done with their
offerings but it'll cost you some time and money ... MS MapPoint *may* be
enough for your needs if you can figure out the APIs, which are documented,
but not well ...

I'm sure there are others;  this is not really difficult stuff but it always
seems to take more time than it really ought to ...

L

If you have the money, go with ESRI which Liz mentioned.  MapInfo has a
following, but I haven't used it in years.

If you have virtually no budget, go for Google Earth.  Driving it from KML
(a variation of XML) is relatively easy.  The API lets you do a lot of
manipulations from outside of GE.  States and regions in KML form is probably
out there.

I know about ESRI and MapInfo and you don't need either. This entire project
can be done using Microsoft Virtual Earth using tiles to color code and
assign regions to multiple managers. We can bind data to tiles and pins and
what have you much less expensive than what has been available from the
desktop and server products from ESRI and MapInfo who have been around a
long time but are not really players anymore once the web enabled platforms
have been released.

In fact an entire line of business that ESRI has enabled to its customers
has now been made obsolete. Sorry I can't recall the name of the ESRI
product that was used for so long and is no longer going to be useful. Its
not ArcServer but something else I just can't remember at the moment.

Anyhow, this can be and probably is a Virtual Earth project. The zip code
data is free from all kinds of sources.