I am searching for a translation/technology company to help translate
my software product into German.  The company needs to be able to work
within my software files as it translates the words the user sees. 
How can I learn who the top companies in this field are?

Hi! Thanks for the question.

Whenever I am looking for top firms for particular industries, I go to
Hoovers.com, a premier site for business information. I have found the
following which are right on to your requirements.

Our first two links specialize in your requirements since they
translate documents for the IT industry.

The Translation Group, LTD 
30 Washington Ave
Haddonfield, NJ 08033
Phone: 856-354-4755
Fax: 856-354-1856
http://www.ttgl.com 
http://www.hoovers.com/co/capsule/9/0,2163,51949,00.html (Please Read:
Description by Hoovers.com)

Lionbridge Technologies, Inc. 
950 Winter St.
Waltham, MA 02451    
Phone: 781-434-6000
Fax: 781-434-6034
http://www.lionbridge.com 
http://www.hoovers.com/co/capsule/0/0,2163,60180,00.html (Please Read:
Description by Hoovers.com)

Here are the other top firms mentioned by Hoovers.com.

Berlitz International, Inc. 
400 Alexander Park
Princeton, NJ 08540
Phone: 609-514-9650
Fax: 609-514-9689
Toll Free: 800-257-9449 
http://www.berlitz.com 
http://www.hoovers.com/co/capsule/1/0,2163,14371,00.html (Hoovers.com
description)

Bowne & Co., Inc. 
345 Hudson St.
New York, NY 10014    
Phone: 212-924-5500
Fax: 212-229-3149
http://www.bowne.com 
http://www.hoovers.com/co/capsule/8/0,2163,11778,00.html (Hoovers.com
description)

SDL plc 
Butler House, Market St.
Maidenhead, Berkshire SL6 8AA, United Kingdom     
Phone: +44-1628-410100
Fax: +44-1628-410505
http://www.sdlintl.com 
http://www.hoovers.com/co/capsule/0/0,2163,102090,00.html (Hoovers.com
description)

If you need more choices, the American Translators Association website
has a list of members you can contact who specialize in the field you
mentioned. The only problem is that the direct link to the search
result does not work. In order ot get to the specific companies,
please follow the following steps.

1. Go here: http://www.americantranslators.org/tsd_listings/#translators
2. Choose #2 or go to Translators Search
3. Choose the radio button "English Into" then choose German.
4. Choose the "Area of Specialization" to be more specific. You can
click on "Computers General" or "Software localization".
5. Then click "Search"

American Translators Association Search Page
http://www.americantranslators.org/tsd_listings/#translators

Search strategy used:
1. Searched on Hoovers.com
2. Searched on Google for the terms: translation services
         
I hope these links would help you in your research. Before rating this
answer, please ask for a clarification if you have a question or if
you would need further information.
         
Thanks for visiting us.          
         
Regards,          
Easterangel-ga          
Google Answers Researcher

Thank you. Very helpful, and nice of you to tell me how to find this
out myself in the  future.