There are many approaches in making a proxy site. If you are just gunna copy and paste script its not making one In order to make one you have to understand what it does. It merely reflects a website off another website. You can get more technical for better anonymity, but at its heart that is what it does. I recommend just using this program.
http://www.rajeshrana.net/2007/08/08/ultra-surf-worlds-best-proxy-surfing-technology/
should get you past just about anything. Its also very hard to block(unless you start passing it around and a lot of students in your school have it. So just keep it to yourself.)