The American Civil Liberties Union is encouraging local defiance of the notorious parts of the National Defense Authorization Act. Among other things, its model legislation “prohibits state/local employees from aiding the federal armed forces in any investigation, arrest, detention, or trial of any person within the United States under the NDAA.”
Check out “State and Local Resolutions Opposing the 2012 National Defense Authorization Act.”
As for nullification itself, why not take a look at the super-interesting book on the subject, selling for a mere ten smackers and written by your host?
(Thanks to Spence McGrath.)