I've installed GTK+, when ./configure it requires libX11. I've looked up on Google but there's no site for downloading. Anyone can help me ?
libX11 is provided in FC3 by the xorg-x11-libs package. If you're building X-based libraries and packages, you'll also want the xorg-x11-devel package.
Why are you building GTK+ when it is available as a standard package in Fedora Core?
Paul.