pass variables to php

I'm using a public set of php files to show to status of my gaming group's TeamSpeak server. One of the variables inside the main php is:

var $serverPasswort = "passwordhere?nickname=usernamehere";

If I delete this variable from the inside of the php file, is it possible for a user to pass this information to the php via the URL? If so, how?

they can write an url like this
"www.yoururl.com?user=theirusername&password=theirpassword"

but it depend how you set your php variable

to avoiding that happen
you must turn of register_global in php.ini configuration

one more thing for safety you should hash/encrypt the user's password, so they can passing it to your url if they dont know
the encrypted password

I just going to add to chyan's post, just as chyan said, if you want to add multiple variables into a link use & for ever variable...
eg