Further to my previous posting, today President Obama signed the Lilly Ledbetter Fair Pay Act.
Lilly Ledbetter worked for Goodyear. Not long before she retired, someone there slipped her a pay schedule showing that male colleagues in the same position were making lots more money than she was. She sued and won at the state level; the case made its way to the Supreme Court, where the court ruled 5-4 that she had to have sued within 180 days of the first time she was paid on a discriminatory basis.
I'm sure you all know that corporate pay just isn't discussed much among workers. You can get fired for doing so. And you're not going to find companies posting their pay schedules, though you might be able to find out the scale for a particular job. Practically speaking, there is no way for workers to conform to that 180 day requirement.
The Lilly Ledbetter Fair Pay Act takes explicit action to fix this injustice: the 180 day period will get reset every time a worker receives a paycheck. In other words, if you discover discrimination that started five years before, and you're still working for the company, you can still seek restitution.
Congress tried to pass this bill during the Bush Administration, and of course it failed. The times, they are a-changin'!