I got the following error when trying to ./configure GIMP 2.0:

checking for libart-2.0... Package libart-2.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `libart-2.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libart-2.0' found

configure: error: Library requirements (libart-2.0) not met; consider adjusting the PKG_CONFIG_PATH environment variable if your libraries are in a nonstandard prefix so pkg-config can find them.
Punisher:~/gimp-2.0.0 #checking for libart-2.0... Package libart-2.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `libart-2.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libart-2.0' found

configure: error: Library requirements (libart-2.0) not met; consider adjusting the PKG_CONFIG_PATH environment variable if your libraries are in a nonstandard prefix so pkg-config can find them.
Punisher:~/gimp-2.0.0 #

I know I have a libart-2.0 package... but what do I need to do here to make it visible?

You need to install the development files. Or use a binary.

Using a binary would be easier.

Well I'm trying to compile for smp... i've got a dual athlon. So what development files do I need to install? I've already got gcc and libraries installed on my system...

You don't need to compile for SMP, or shouldn't do. How you install the developer tools varies from distro to distro, on Fedora you just check the boxes in Add/Remove Packages.

Are you *sure* you need to compile? Gimp will use multiple processors with no special compiling necessary.