I've had miserable experiences trying to use WxPython or GTK under both RH9 and Fedora Core 3. There is some version skew between the installed versions of GTK and the WxWidgets on the distro site. I made some progress by installing an old version of GTK but there was still some problem. I decided it wasn't worth the hassle.
Unless there's some serious importance to making your gui very slick, I think the only Python gui toolkit worth considering is Tkinter. It has drawbacks but it's the one that seems to work the most consistently with the least hassle. -- http://mail.python.org/mailman/listinfo/python-list