doing a preg_replace in PHP - help needed!

I have some chat software that uses this line of code to turn "http://www.someurl.com" into a hyperlink

Here's the current code:
$ret = preg_replace("#(^|[\n \]])([\w]+?://[\w\#$%&~/.\-;:=,?@+]*)#ise", "'\\1<a href=\"\\2\"" . $target . ">' . pfc_shorten_url('\\2') . '</a>'", $ret);

I can't figure this out I was wondering if a pre_replace wiz could do something that matches a youtube link to a certain URL:
like from
http://www.youtube.com?v=DFSLKJ

to

<a href="#" onclick="opentube('http://www.youtube.com?v=DFSLKJ')"><img src="arbritrary_image"></a>

 

function riptube($link) {
		$tubefunction = "<a href=\"#\" onclick=\"opentube('\\1')\"><img src=\"arbritrary_image\"></a>";
		if (preg_match("/^http:\/\/www.youtube.com\?v=([A-Z]+)$/", $link)) {
			return preg_replace("/(.+)/",$tubefunction, $link);
			break;
		} else {
			return FALSE;
			break;
		}
		return FALSE;
	}

Code (markup):

If I understood you correctly, you mean something like this?

 

hmm not exactly, how about this

right now this code:
$ret = preg_replace("#(^|[\n \]])([\w]+?://[\w\#$%&~/.\-;:=,?@+]*)#ise", "'\\1<a href=\"\\2\"" . $target . ">' . pfc_shorten_url('\\2') . '</a>'", $ret);

matches an "xxxx://yyyy" URL at the start of a line, or after a space.

how would I modify it to match "xxxx://yyyyyoutube" instead? (the four x's and four y's stand for letters/symbols)

 

can you give me example...
input string and your output string...

 

with this code:

$ret = preg_replace("#(^|[\n \]])([\w]+?://[\w\#$%&~/.\-;:=,?@+]*)#ise", "'\\1<a href=\"\\2\"" . $target . ">' . pfc_shorten_url('\\2') . '</a>'", $ret);

input string:

"blaa blaa arbitrary text http://www.website.com blaa blaa"

output string:

"blaa blaa arbitrary text <a href="http://www.website.com">http://www.website.com</a> blaa blaa

i want to modify that pre_replace so that it only does it for youtube links

 

ah nevermind, I got it to work by doing this

$ret = preg_replace("#(^|[\n \]])([\w]+?://www\.youtube[\w\#$%&~/.\-;:=,?@+]*)#ise", "'\\1<a href=\"\\2\"" . $target . ">' . pfc_shorten_url('\\2') . '</a>'", $ret);