Hi i have recently discovered that my site was on some one elses website, i have checked his source code so but it wasnt through iframes so it must be through server side technology. i was wondering if theres a way to block this from happening.

Not really I think. Suppose he's doing this with cUrl, then there is a way to make you think it is just a browser. You can block him by IP or something, but that won't stop someone else from trying to do the same.

on apache servers, the following code may help
part of a .htaccess file
mod_rewrite is the relevant section,

RewriteEngine On
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !www.mysite.com [NC]
RewriteCond %{HTTP_REFERER} !mysubdomain.mysite.com/ [NC]
RewriteCond %{HTTP_REFERER} !mysecondsubdomain.mysite.com/ [NC]
RewriteCond %{HTTP_REFERER} !www.someotherpermittedsite.com/ [NC]
RewriteRule \.(jpeg|jpg|gif|bmp|png|wmv|asf)$ - [F,NC]

<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType text/html "access plus 2 days" 
ExpiresByType image/gif "access plus 60 days"
ExpiresByType image/jpg "access plus 60 days"
ExpiresByType image/png "access plus 60 days" 
ExpiresByType application/x-javascript "access plus 60 days"
ExpiresByType text/css "access plus 60 days"
ExpiresByType image/x-icon "access plus 360 days"

full docs not really sure if the bandwidth theft mod_rewrite rules will help against curl use