What are all the internet related companies in New York city have the
following criteria:
more than 40 employees 
less than 300 employees
Have at least 20 employees who are programmers
predominantly use Unix based technologies
Use technologies other than Java
Did not have any major layoffs in the past 6 months

I don't currently have a subscription, but Hoover's Online at
http://www.hoovers.com/ allows you to search for much of this, though
probably not for all of your requirements.

From the front page, you may click "advanced" search where you can
search for companies by the number of people they employee, their
location, their category of work, keywords, etc.

It will require a subscription, however, to Hoovers Pro.

Speaking only from a few personal past experiences the kind of
information you are requesting is for the most part available only
from List generating companies (i.e. companies that compile mailing
lists) and these usually charge a fee based upon the size of the list
you want and how current you want the data to be.  I'm sure
governmental agencies such as the IRS or the Better Business Bureau
would have this kind of data but it is not freely available on the
net, one would be encouraged to contact them in regards to each
agency's particular requirements for information requests.  Do not
know if this helps at all but hopefully might get you going in the
right direction.

Hello inetnyc-ga,

Here are three great places to find the exact information you are
looking for. I know this because our company (the company I work for
and not Google) use 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. Each offer free searches
and they offer more information if you pay them.
 
Hope that helps you out :-) and thanks for the questions!
 
Regards, 
 
Interceptor-ga