Super easy way to add custom fields to the user profile on WordPress. This will take you 3 seconds to implement.
function modify_contact_methods($profile_fields) {
// Add new fields - this can be as many as you like
$profile_fields['cool_new_field'] = 'Twitter Username';
// Remove old fields
unset($profile_fields['some_existing_field_you_hate']);
return $profile_fields;
}
add_filter('user_contactmethods', 'modify_contact_methods');
//And if you want to retrieve this new variable
echo get_the_author_meta('cool_new_field');