Day to Day, March 29, 2006   Thousands of students walked out of classrooms across the nation on Tuesday to protest proposed changes to immigration law seen by many as a crackdown on illegal immigrants. In California’s Central Valley, protests are coordinated among remote agricultural towns by text messaging and MySpace chat rooms. Sasha Khokha of member station KQED examines the grass-roots protest organization and what the students are protesting against.