$.extend({
  getUrlVars: function(){
    var vars = [], hash;
    var hashes = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&');
    for(var i = 0; i < hashes.length; i++)
    {
      hash = hashes[i].split('=');
      vars.push(hash[0]);
      vars[hash[0]] = hash[1];
    }
    return vars;
  },
  getUrlVar: function(name){
    return $.getUrlVars()[name];
  }
});

URLが以下の場合

http://www.example.co.jp/?hoge=Value1&huga=Value2

配列で取得

var get = $.getUrlVars();
var hoge = get['hoge'];
var huga = get['huga'];

単体で取得

var hoge = $.getUrlVar['hoge'];
var huga = $.getUrlVar['huga'];

http://jquery-howto.blogspot.jp/2009/09/get-url-parameters-values-with-jquery.html