What makes PHP messy in my head is not the "shorthand-effect". It's that my head has trouble switching back and forth between HTML and PHP. I'm going to try to get my editor to use a different colored background for PHP and HTML, that should make some of the "special character alphabet soup" a bit clearer.
My chat works fine now, feel free to check it out at
http://rpglab.net/index.php. It's in Swedish, but if you click on "chat", click on the link that appears, get the file, then click chat again it should work nicely even if you don't speak Swedish.
Edit: No need to register a user, just set your name in chat options.
It is IE only for the moment, but if you don't use IE, the file you downloaded also contains a windows stand-alone client.
As far as I know, it is the only threaded chat today. The oldest entries will be removed (200 kept, can be changed by the user), causing the threads to dynamically grow and adapt to the discussion. Difficult to explain, but works really nicely.