On March 29th, 2012, the Secretary of Homeland Security designated Syria for Temporary Protected Status (TPS). Syrian nationals that have been continuously residing in and physically present in the United States since March 29th, 2012 are eligible to apply for TPS.
The registration period for TPS is from March 29th, 2012 through September 25th, 2012.
This applies to Syrian nationals who are in the United States, whether you have a valid visa or have overstayed your visa.