preg_replace() issue

1)

function filter() {

if($this->post['a'] == "savenews") {
$this->post['summary'] = preg_replace("!\[url\](.*)\[/url\]!","<a
href=\"\\1\">\\1</a>", $this->post['summary']);
}

-----------------------

2)

global $nwedst;
$nwedst = str_replace("<br>\n", '', $dat->summary);
nwedst = preg_replace("!\<a
href=\"http://(.*)\">(.*)\</a>!","http://\\1", $nwedst);




1 takes a full news post and changes ... into <a
href="...">...</a> and saves the news post
2 takes the full news post and recalls it, changes <a href="...">...</a>...
into ...


1 is used when making a new news post, 2 is used when editing a news post
(making the post user friendly and easy to edit)

2 seems to only replace the first <a href="..."> and the last </a> when
there are multiple links. That's the first of my problems. The second is
that I would like to change my code so that it changes $2
into <a href="$1">$2</a> and back again but i don't know how to change
multiple things with preg_replace().


plz help,
Darkstar