I was laid off (with zero days' notice) by a small pharmaceutical
company two weeks after returning from maternity leave.  I was told
that my territory had no potential for growth, and I was one of 3
employees in my district to be let go.  However, I had finished second
in my district and 24th in the nation for compensation for the 3rd
quarter (the last quarter I was eligible for, as I missed most of the
4th quarter due to maternity leave).  I consistently posted better
numbers and growth percentages than one of the people that will be
taking over part of my territory.  Another one of the employees that
was let go had also missed a significant amount time due to surgery. 
Finally, the HR director who was in on the conference call went out of
his way to point out that this had nothing with my being on maternity
leave.  Needless to say, I don't believe that.  Do I have a case?

I am not an attorney.  However, I do have some personal experience in this area.

A good method for getting an idea whether or not you have a case is to
file a complaint with the Equal Employment Opportunity Commission.  If
the investigator who takes your charge of discrimination believes you
have a case, they will investigate and report back to you.  Nearly all
laws enforced by the EEOC require that you file a charge before you
can file a private lawsuit in court anyway.  In most cases, you must
file a charge of than 180 days from the date of the alleged violation
in order to protect your rights.

When you file your charge, the EEOC can provide you with a list of
attorneys practicing in this area.  They are unable to recommend a
particular one, though.

My advice to you is to gather up any and all supporting documents that
corroborate the fact that you were on maternity leave and your
performance at work.  A written statement from the other employee
about their surgery and subsequent dismissal would also be helpful.  A
concise written statement of your claim of discrimination is also
helpful to bring because you will need to complete a form describing
the alleged discrimination.  Other information you need, along with
information about the charge filing process, can be found at:

"Filing a Charge of Employment Discrimination" The US Equal Employment
Opportunity Commission (August 13, 2003)
http://www.eeoc.gov/charge/overview_charge_filing.html

Another important piece of information for you to find out is how many
other employees were laid off by the company as a whole at the time
you were dismissed.  The more people that were laid off when you were,
the more likely it is that the company will get away with what they
have done because their argument that the layoffs were not
discriminatory will be more plausible.  If the company is in
significant financial distress, your case becomes much more difficult.

Above all, before making a charge, be able to present the
circumstances and your evidence in a concise, factual, and unemotional
way so as to be as convincing and easy-to-follow as possible.

Another link you may find useful is: "Pregnancy Discrimination" The US
Equal Employment Opportunity Commission (December 10, 2004)
http://www.eeoc.gov/types/pregnancy.html

Finally, there may be laws in your state and/or city that are
applicable.  Your local EEOC field office may be able to provide you
with information.  Otherwise, contact an attorney in your area.

Sincerely,

Wonko