Jack McClellan, 45, who calls himself a pedophile but says he has never sexually touched a child, has created Web sites in Seattle and Los Angeles detailing how and where he trolls for children.  He was spotted at a fair in Santa Clarita.  He recently emerged from the Social Security office on Olympic Boulevard.  He tapped away on a computer at the library in Mar Vista.  Warnings have gone out. Signs have been posted.  And yet unlike convicted sex offenders, who are required to stay away from places that cater