Converts a plain text Twitter tweet into html to <a> tags for URLs, #links and @links

getLinksFromTwitterText.php

<?php
/**
 * Takes a string argument, which may include URLs, twitter #links or twitter @links,
 * imbeds html <a> tags into the string and returns it.
 * 
 * @param  [type] $string [description]
 * @return [type] $string [description]
 */
function getLinksFromTwitterText($string)
{
    // Converts a plain text url to a hyperlink
    $string = preg_replace('~(?:(https?)://([^\s<]+)|(www\.[^\s<]+?\.[^\s<]+))(?<![\.,:])~i', '<a href="$0" ' . $target . ' " title="$0">$0</a>', $string);
    // Converts hashtags to a link
    $string = preg_replace("/#([A-Za-z0-9\/\.]*)/", "<a href=\"http://twitter.com/search?q=$1\" " . $target . " >#$1</a>", $string);
    // Converts @user to a link
    $string = preg_replace("/@([A-Za-z0-9\/\.]*)/", "<a href=\"http://www.twitter.com/$1\" $target >@$1</a>", $string);
    return $string;
}