Bookmarking pages

Hi all, again, I need to be able to have working bookmarkable pages in a system. The user has session ID's which have to time out, so when they do the user is kicked out of the system. But i've been asked to set it up so that after a user gets kicked to a login screen becasue they have an expired/invalid session id, to let them go back to the page they where on before getting booted. No all of the non-session id variables will be in the $HTTP_GET_VARS array (right ?), but how do I get the file that the user has just come from ? Jason -- Hofstadter's Law : "It always takes longer than you expect, even when you take Hofstadter's Law into account."