Wrongful termination in an 'at will' employment state is extremely difficult (and potentially expensive) to pursue without good legal counsel, in my opinion. Best bet (again in my opinion) is to contact your local labor board first with specific questions about your particular circumstances to see if there are certain procedures required first. (Filing a complaint with the EEOC, for example.) It would depend on the reasons stated (if any) for your termination, your employer's policy and even the particular jurisidiction involved; if the stated reasons can be directly related to standard federal discriminatory statutes,you may or may not prevail .. eventually. If this sounds vague, you have a pretty good idea of just how difficult it can be. Help for employers with california at-will employment is strictly for informational purposes; while it's intention is to educate employers, it may help shed some light on your situation as well. It is, of course, no substitute for legal counsel .. a prelim consultation would most likely better address your specific questions and concerns.

Good luck.