How many businesses are there in the US with 10-99 PCs on their network?
Where can I get a list of these businesses?

Since this information is very lucrative you won't find a
comprehensive list on the web. You'd be better off asking a marketing
company this question, as they would be able to give you a more
accurate list along with addresses for a fee. Something like this
company http://www.mailorder.com/acgservices.htm

Hello jaymann-ga,

I would of given this as an answer and not a comment but the Google
Answers website would not allow me to post anything other then a
comment. Since I use these resources on a daily basis I thought that I
would give them to you so you could also use them :-)

Here are three great places to find the exact information you are
looking for. I know this because our company uses them all the time.

Dun and Bradstreet (http://www.dnb.com) where you get your DUNS
number.

"D&B's information and technology solutions help businesses reduce
credit risk, find profitable customers and manage vendors efficiently.
We have the largest company database available, with information on 70
million companies worldwide - for your credit, marketing and
purchasing decisions."

Zapdata has everything that you are looking for at
(http://www.zapdata.com)

Once you register you can look up company profiles (limited) and get
the information that you need.

The third choice is Hoovers online (http://www.hoovers.com)

Hoovers Online is a subscription-based service that can also get you
the information that you need.

Any of the 3 website that I mentioned above can help you get the exact
information that you need about any company.

Hope that helps you out :-)

Regards,

Interceptor-ga

Thanks biba and interceptor. Jay.