Check out the IRS website (www.irs.gov) for their information on Identity Theft. They do have a process to provide a pin for someone that has been victimized in this way - I just can't remember if you can get that before you have issues with someone filing with your number or only after it has happened. Not everyone is in a position to be able to file now that might have been hit by this breach.
Here is a link: http://www.irs.gov/Individuals/Identity-Protection