The session variables are available on the Bindings panel. To open the bindings panel, go to Window Bindings.
In the bindings panel, expand the session collection, select the binding you want and dragt it to the page where you want it to display.
To hide the binding if the user is not loged in, select the code in design view, then on the server behaviors panel, click the plus button and select SecurityAssist -> Show Region. form the list of rules select the Logged in rule so the binding will only show if the user is logged in.