Guile-Gnome has a mailing list, which for historical reasons, still is the one that was created and used for the Guile-Gtk project. Please send us your questions, patches and/or requests for improvements there. You may subscribe, unsubscribe and read the archives here.
Guile-Gnome has a bug tracker. You may submit bug reports using the bug tracker or, if it's easier for you, using the mailing list.
You can sometimes find some of the hackers hanging out on #guile on irc.freenode.net.