$.fn.floating = function(options){
    
    options = $.extend({
        wait: 100,
        minDuration : 100
    }, options);
    
    return $(this).each(function(){
        var $this = $(this);
        var boxTop = function(){return $this.offset().top};
        var startTop = boxTop();
        
        var timer;
        
        $(window)
            .scroll(function(){
                if(timer) return;
                timer = window.setTimeout(function(){
                    var scrollTop = document.body.scrollTop || document.documentElement.scrollTop;
                    var nowTop = boxTop();
                    var targetTop = scrollTop + startTop;
                    var duration = Math.max(options.minDuration, Math.abs(targetTop - nowTop));
                    
                    $this
                        .animate({
                            top: targetTop + "px"
                        }, duration, function(){
                            timer = 0;
                        });
                }, options.wait);
            });
    });
};

<?php
/*
Plugin Name: custom posts
Plugin URI: http://ichi.fool.jp/blog/
Description: 現在のクエリを変更してループに。
Version: 0.1
Author: ichi
Author URI: http://ichi.fool.jp/blog/
*/ 

function &custom_posts($query){
    if(!$query) return;

    $temp_query_vars = $GLOBALS['wp_query']->query_vars;

    if(!is_array($query))
        parse_str($query, $query);

    $query = array_merge($temp_query_vars, $query);

    unset($GLOBALS['wp_query']);
    $GLOBALS['wp_query'] =& new WP_Query();
    return $GLOBALS['wp_query']->query($query);
}
?>