重用.NET网站中的代码（app_code文件夹）

I need to use some classes inside the app_code folder of a website project in visual studio 2008. I need to access this code from a class library project in the same solution. I cannot add a reference to the website, and I'm not sure of the easiest way to use the classes that already exist here. Do I need to move it to a class library?I need to use some classes inside the app_code