But see also the parse_url() function.
or
$url='http://www.phpbuilder.com/board/newreply.php?s=&action=newreply&threadid=10222566#post10272025';
if(strpos($url,'?')) $url=substr($url,0,strpos($url,'?');
if(strpos($url,'#')) $url=substr($url,0,strpos($url,'#');
echo $url;