parse string variable for URL

I looking for help on parsing a variable that contains a text for http://any.url.whatever.

Can someone please help?

I forgot to mention that once parsed I need to make that url into an href so when i pull it out of the database it prints a link

$url =
"<BODY>http://www.al-e_x.com/wh_at.php?what=2123123123

ftp://www.al-e_x.com/wh_at.php?what=2123123123<I>
mailto://alex@what_who_where-xyz.com</BODY>";

$url = eregi_replace(
"((http|mailto|ftp):\/\/[^{[:space:]<>]{1,})",}
"<a href='\1'>\1</a>",$url);

print $url;
?>