Access rights for php files on Linux?

Well, I have encounterd a problem which is quite big (for me), so I hope I find help here. My setup is a Linux Machine, running Apache with php as a module. In order for the webserver to parse the file, i have to give read permission to world. This is a problem, because about 100 people have shell access and could then just cat /www/myphpfile.php, and would thus get passwords which i dont want to share (like mysql password in the phpmyadmin config file) and general access to my code. Also, the different users on the machine want to be able to host php files with everyone else being able to read them. Is there any way i can actually do that? I must say that i am rather new to all this stuff, so i am really confused as what to do, and i would appreciate any help.. Thanks in advance... Daniel