PHP Redirector Anyone??

Hello,
 
I need a PHP redirector for my server in which I host multiple web
sites as follows:
 
Site 1
====
Local Path: /var/www/htdocs/site1
Server IP: 192.168.1.10
URL: www.site1.com
 
Site 2
====
Local Path: /var/www/htdocs/site2
Server IP: 192.168.1.10

URL: www.site.com
 
When someone refers to either www.site1.com or www.site2.com, I need
them to be redirected to a specific local directory respectively. Can
someone help doing this via PHP?
 
Thanks,
Shaffin.