Hollywood's catalyst for change

Al Gore calls her "the catalyst" behind "An Inconvenient Truth," and Laurie David has emerged from the shadows as Hollywood's premier climate change crusader. She's signed up petitioners at www.stopglobalwarming.org in an effort to influence policy on global warming, infiltrated TV studios to put global warming into plots a and worked with musicians to talk about the issue from the stage. Now, she's on tour with Sheryl Crow, taking the message to college campuses - and hoping the word percolates up from the citizens to the presidential candidates.