Anyone mess around with PHP and GTK yet?

http://gtk.php.net

Yep, but it has a lot of work to do :). I'll probably make use of GTK a little more once it becomes a little more stable. I think giving it a little more time will reveal some pretty awesome results :).

wuts the alternatives of gtk ?

There are none.
php-gtk is really cool. You can even use tools to create your (kind of) workspace and then later on combine/use it with your script.
It offers a lot potential, but may be only interesting who don't know C/C++ yet, so they can script in their preferred language - php :) .