This came up in August 2013 as part of fighting an issue with inbound email.
var rec = new GlideRecord('sys_user');
rec.addQuery('active',true);
rec.addQuery('locked_out',true);
rec.query();
var counter=0;
while (rec.next()){
counter++;
rec.locked_out = false;
rec.update();
}
gs.print("counter is: " + counter);