Passing variables from script to script

Hi folks, surely this question has already been answered many times before in this ng, but nevertheless: I want to pass variables from one .php to another .php script. But I do not want to use either the http://localhost/target.php?var1=test&var2=test2 nor the POST method. I would like to pass over general variables like usernames and passwords for several MySQL-connects; obviously it is not a good way to pass these vars via the mentioned ways. What else does PHP offer? Are there any other methods? Can I define these vars as some kind of "global variables" in any ini-file? THX for your support! Stefan.