new to PHP: add variable to session...?

Hi I have an include file which submits generic forms The first line of the include is $url=$sess->url(sprintf("$PHP_SELF")); so the page reloads before the submit process takes place. I want to keep a variable value in this reloaded page but it is always being lost. I don't want to modify the $url as this would effect other forms being submitted using the same include. I have tried using global variables but can't seem to get it working properly Any ideas?