I'm interested in bringing together data to show which Congressional
districts have the highest percentage of Arab Americans, Jews, and
Iranian Americans. Then, I'd like to list for each district any large
companies that have their headquarters or an office in that district.
I'll do the compilation. Can you point me to the right references
either online or in the library?

This is really tricky, jsimmons-ga.  I know I have seen the data you
are seeking on a state level in the New Jersey Municipal Data Book (or
a similar source).  You may be able to find data books like this for
other states, too, and then go from there.  Once you have the
demographic data, it's easy to find the companies from there.

Good luck!

Scott
scottso-ga

Here is some demographic information on Congressional Districts

http://www.census.gov/prod/www/abs/congprof.html