$realname = "This is the string to be made SEO friendly!"

$seoname = preg_replace('/\%/',' percentage',$realname);
$seoname = preg_replace('/\@/',' at ',$seoname);
$seoname = preg_replace('/\&/',' and ',$seoname);
$seoname = preg_replace('/\s[\s]+/','-',$seoname); // Strip off multiple spaces
$seoname = preg_replace('/[\s\W]+/','-',$seoname); // Strip off spaces and non-alpha-numeric
$seoname = preg_replace('/^[\-]+/','',$seoname); // Strip off the starting hyphens
$seoname = preg_replace('/[\-]+$/','',$seoname); // // Strip off the ending hyphens
$seoname = strtolower($seoname);

echo $seoname;