Show names of logged-in users

[Anon]

I'm looking for a possibility, to show all loginnames of those users, who have logged-in via a login-script.
AND, if they leave the website, their name should disappear (That's my main problem!)
I'd prefer a myql-database-connection script, but anything else that works is fine, too.
Anybody got an idea? Hope you can help me!
Thank you so much!

German: Ich suche nach einer Möglichkeit, die Loginnamen aller User, die sich über ein Login-Script angemeldet haben anzuzeigen.
Sobald diese die Website verlassen, sollen die Namen aber wieder gelöscht werden (Das ist mein Hauptproblem)
Am besten wäre, wenn das ganze auf einer Datenbank beruhen würde!
Hat irgendjemand eine Idee, wie man das realisieren könnte? Es wäre mir eine RIESEN Hilfe!!

[kparker]

This topic has been discussed here at great length.

if they leave the website, their name should disappear
(That's my main problem!)

This is the undoable part, since HTTP is (and will continue
to be) stateless. The best anyone can do is to track the
page loads on a per-user basis, including a timestamp, and
then age them based on whatever time interval you want.