CentOS 5 Server :: Allow Apache To Access The Internet?

We have Apache installed on CentOS 5.3 in our laboratory. Indeed the server is running fine for almost two years since it is actually the first CentOS 5 that was released just regularly updated. Now, most of our applications are custom made PHP applications and until now we somehow managed to avoid using PHP to fetch files that are on the internet itself. But now we are desperate because we need to allow PHP to fetch files through Apache but it seems as if Apache is not allowed to make a connection to the outer world. Additionally we use a proxy server to connect to the outer world so right at the beginning http_proxy is used to set that environmental variable. And for the root user it all works fine after that but it seems as if the apache user is not allowed to access the internet. Just to make a remark our web server can be accessed from the outer world so its a one way street for now.