Adding or Removing Profile Fields

function my_contactmethods( $contactmethods ) {

	// add
	$contactmethods['twitter'] = 'Twitter';
	$contactmethods['facebook'] = 'Facebook';
	$contactmethods['blog'] = 'Blog';

	// remove
	unset($contactmethods['aim']);
	unset($contactmethods['jabber']);
	unset($contactmethods['yim']);

	return $contactmethods;
}
add_filter('user_contactmethods','my_contactmethods',10,1);