I've managed to get my IP number, by writing a php page and getting the REMOTE_ADDR string.
$clientip = $_SERVER['REMOTE_ADDR'];
echo 'phone ip:'.$clientip;
what i would like to know is whether i could use this ip number to track this specific phone. i.e. as a login name/password. so if a user logs on to my server today and uploads some files, in a month's time, then can come back and get only the files they uploaded. or will their ip change, or is it shared by other mobile users?