I am trying to build GTK+ 2.0. In order to do so I obtained the 3 prerequisite libraries (pango, ATK, and GLIB) I was able to build GLIB and PANGO but when I attempt to build ATK it gives me the following error message:

checking for pkg-config... (cached) /usr/bin/pkg-config
checking for GLIB - version >= 2.0.0...
*** 'pkg-config --modversion glib-2.0' returned 2.8.1, but GLIB (2.6.4)
*** was found! If pkg-config was correct, then it is best
*** to remove the old version of GLib. You may also be able to fix the error
*** by modifying your LD_LIBRARY_PATH enviroment variable, or by editing
*** /etc/ld.so.conf. Make sure you have run ldconfig if that is
*** required on your system.
*** If pkg-config was wrong, set the environment variable PKG_CONFIG_PATH
*** to point to the correct configuration files
no
configure: error:
*** GLIB 2.0.0 or better is required. The latest version of
*** GLIB is always available from-----------. If GLIB is installed
*** but not in the same location as pkg-config add the location of the file
*** glib-2.0.pc to the environment variable PKG_CONFIG_PATH.

I am a bit unfamiliar with Linux and am unsure how to proceed from here. I'm looking for some help on just how to proceed from here in order to try and solve this problem.

you have two versions of gliband pango new ones are most likely in /usr/local and old ones in /usr

best read latest Beyond Linux From Scratch book about this stuff
i would uninstall all of gnome before proceding
so many people go down this road and get very confused