Recent versions of Devhelp use gecko instead of gtkhtml, so now it can handle the links in gtkmm's html documentation. For instance, the search feature now works. It's useful.
Platform Bindings
We'll have pygtk in the GNOME Plaform Bindings for 2.7/2.8, That covers GTK+ and libglade, though nobody is claiming mainantership of the extra gnome-python tarball.