关于正则，求好手帮助 _PHP

关于正则，求高手帮助
如例:
http://bbs.csdn.net/topics/new?forum_id=PHP
http://www.bdyy.cc/detail/?20236.html
http://www.qq.com/html/?20236.html?id=88888

preg_match('/(http:\/\/)(.*)(\/)/',$rrr,$matches);

如何分别正则出:
bbs.csdn.net
www.bdyy.cc
www.qq.com

------解决方案--------------------

$s=<<<txt

http://bbs.csdn.net/topics/new?forum_id=PHP

http://www.bdyy.cc/detail/?20236.html

http://www.qq.com/html/?20236.html?id=88888

txt;

preg_match_all('/http:\/\/([^\/]+)\//s',$s,$matches);

print_r($matches[1]);

Array
(
    [0] => bbs.csdn.net
    [1] => www.bdyy.cc
    [2] => www.qq.com
)
------解决方案--------------------
preg_match('/http:\/\/([^\/]*)/i',$rrr,$matches);