If you are looking for a script you may check
our little peace of coded function: getpath()
or the (pretty old) "php Light Chat (1.5 kb zip)" (10 lines of code for a chat)
I suggest you choose this one "Light Php4-Flash chat" that is a subproduct of the latter Php3 Light Chat.
This is far more stable. (includes file lock check) and uses flash as the GUI tecnology.
You may also check our great News Site
(if you understand italian):
NotiziarioWeb.it
Le migliori notizie da tutto il mondo