The PHP-GTK Community website has an announcement about the launch of a new PHP-GTK related forum at http://phpgtk.opsat.net/.
Another PHP-GTK forums site has sprung up [...] to provide a very informal environment, where posting will not need registration, or the use of a real identity. The site currently offers 3 PHP-GTK sections, and one general section.
The forum is also linked to back and forth with the PHP-GTK Community site whenever a a cross-post is made from the forum.