I recently put in my letter of resignation within the county of Los
Angeles California. However, when I was hired, I signed a letter of
employment that stated I would give a "30 day notice upon separation."
The letter is somewhat formal, both myself and employer signed the
document.

I put my letter of resignation in for only two weeks, instead of 30
days per the agreement. Can I be sued or held liable for breach of
contract under California law? My employer was not happy, but I
insisted that our agreement was not a legal document, just an
agreement that I have chosen to break. Does the ?at will? law protect
me in anyway? Are there any past court cases in California that I can
refer to? Am I actually breaking any laws?

I am not a lawyer and this is not legal advice, however I have been
employed with various govermental agencies in Los Angeles for the past
13 years, including human resources.  My experience has been that the
30 day notice is primarily so that the work and job responsibilites
can be transfered to another person within that time frame.  I have
never heard of any legal action against any employee that decided just
to fly the coop without any notice at all, unless it involved criminal
activity as well.

In your case, if you are providing only 2 weeks notice, it is possible
that if you have accumulated TOWP (Time Off with Pay) banked, the
department may request that the TOWP for the 2 weeks you should have
worked be taken out of your bank, essentially as if you were taking
vacation the last two weeks you were supposed to be there.  But that
is waived is cases where an employee is leaving in advance of a layoff
situation or similar circumstance.  I will be interested in seeing
what other response you get also.  Good luck.