How can I identify and locate specific service bureaus who print and
mail bills, invoices and statements for billers and mail them to
consumers. These companies format data from billers and actually print
and mail them to the biller's consumers. For example a cable company
may have their data sent to a service bureau who prints the bill and
sends it to the consumer. The largest service bureau is OTS (Output
Technology Solutions. I am looking to locate service bureaus who
generate between $5 and $50 million in revenue per year. In addition,
I am very interested in service bureaus located in the New York metro
area as well as others located through out the entire U.S. These
service bureaus need to print and mail statements from billers like
credit card companies, banks, brokerages, cable, utilities, etc.

Hello, and thanks for asking the question.

There appear to be quite a few companies that provide outsourcing
services for statements and bills. In addition to Output Technology
Solutions, which is now, incidentally called DST Ouput (
http://www.output.net/index.html ) and is a division of DST Systems,
here are several I have found:

Output Services, Inc., of Boulder, CO
http://www.outputservices.com/

VFI Statement Processing, of Louisville, KY
http://www.vintage-vfi.com/esp.htm

Payformance Corporation, of Jacksonville, FL
http://www.payformance.com/default.asp

Drew & Rogers, Inc., of Fairfield, NJ
http://www.drew-rogers.com/index.html

Gemisys Financial Services, of Denver, CO
http://www.gemisys.com/statement.htm

BillingPros.com, of Lake Elsinore, CA
http://www.billingpros.com/billing_services.htm

As you can see, there are a number of companies offering this service.
 If you use the search strategy that I outline at the end of this
answer, you will no doubt find others, but these pop up near the top
of the list.  Drew & Rogers is the only one that I have found (so far)
in the New York area.

Now, you mentioned that you are particularly interested in service
bureaus that are between $5 and $50 million in revenue, and
unfortunately, that is more difficult to determine.  With the
exception of DST Output, all the companies I listed are private
companies, and their revenue is therefore not made public.  I think
that it is reasonable to assume, however, that they are all under $100
million or they would have been lured down the IPO yellow brick road. 
But I cannot say that definitively.

Because DST Output is a division of a public company, I was able to
get some revenue numbers for it.  From the 2001 Financial Report of
DST Systems ( http://www.dstsystems.com/in/2001_annualrep.pdf ), their
total revenue was $1.66 billion, of which Ouput Solutions comprised
35%.  This amounts to $581 million, which is no small chicken!

While doing the research, I came across several companies that focused
on statement processing for a particular market niche, namely the
medical profession:

eInformatics
http://www.einformatics.com/billing_service.htm

Data Strategies Incorporated
http://www.e-dsi.com/

As you specifically asked how you can find such outsourcing companies,
here is the search strategy I used:

Keyword searches:
"statement processing services"
"statement outsourcing"

Directory searches:
http://directory.google.com/Top/Business/Business_Services/Outsourcing/Finance/

Finally, you may notice that a number of the companies I listed also
are moving into electronic bill presentment.  I don't know if that is
of any interest to you, but if you are searching for an outsourcing
provider, or are thinking of going into this line of business, it is
something you should consider as the direction this industry is going.
 In any case, there is a national organization that deals with this
industry, which can be another source for information on companies in
this space.  That organization is:

NACHA - The Electronic Payments Association
http://www.nacha.org/

Another good source is one of the industry trade magazines:

Document Processing Technology
http://www.dptmag.com/

I genuinely hope this answers your question.

Another Print & Mail company that services large customers is Per Se
Technologies, www,per-se.com

Would you like to outsource your function to Sri Lanka? You will be
surprised about the quality labour and the cost.

InfoSend, Inc. is another Print and Mail option.  They specialize in
customization and personalized customer service.  They also provide
EBP (Electronic Bill Presentment).  Located in Orange County,
California.
See http://www.infosend.com