http://www.webxml.com.cn/webservices/qqOnlineWebService.asmx?op=qqCheckOnline
http://zhaowenbinmail.blog.163.com/blog/static/3908086201032223235404/
http://taobeibei.iteye.com/blog/586964
http://www.blogjava.net/tunaic/archive/2009/05/18/271318.html