URLs as Links with Regular Expressions using PHP Function.

I'm using this PHP function to redirect text URLs as Links with Regular Expression validation. Just five lines of code, It's very useful.

To_Link.php
Contains PHP Code $text value validating with Regular Expressions 

<?php

function To_Link($text)
{
$text = html_entity_decode($text);
$text = " ".$text;
$text = eregi_replace('(((f|ht){1}tp://)[-a-zA-Z0-9@:%_\+.~#?&//=]+)',
'<a href="\\1">\\1</a>', $text);
$text = eregi_replace('(((f|ht){1}tps://)[-a-zA-Z0-9@:%_\+.~#?&//=]+)',
'<a href="\\1">\\1</a>', $text);
$text = eregi_replace('([[:space:]()[{}])(www.[-a-zA-Z0-9@:%_\+.~#?&//=]+)',
'\\1<a href="http://\\2">\\2</a>', $text);
$text = eregi_replace('([_\.0-9a-z-]+@([0-9a-z][0-9a-z-]+\.)+[a-z]{2,3})',
'<a href="mailto:\\1">\\1</a>', $text);
return $text;
}

?>

index.php
You have to include To_link.php. Using function To_Link('You Text and URL')

<?php

include('To_Link.php');

$text='jQuery and Ajax best 9lessons http://tinyurl.com/naottn';

echo To_Link($text);

?>