First, you need to install the Nvidia binary drivers from RPMFusion.  The below commands should handle that:

sudo rpm -Uvh http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-18.noarch.rpm
sudo rpm -Uvh http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-18.noarch.rpm
sudo yum -y install kmod-nvidia xorg-x11-drv-nvidia-devel

Then, you need to download and install the CUDA software from https://developer.nvidia.com/cuda-downloads

Install with the following command:

chmod ugo+x cuda_5.0.35_linux_64_fedora16-1.run
sudo ./cuda_5.0.35_linux_64_fedora16-1.run -override compiler

Accept the license, answer n to installing the driver, y to the Toolkit, and y to Samples, I left installation paths at default.

Create a file /etc/ld.so.conf.d/cuda.conf that contains the below two lines:

/usr/local/cuda/lib64
/usr/local/cuda/lib

Download the latest source for cgminer and compile with the following command below:

CFLAGS=-I/usr/local/cuda/include LDFLAGS=-L/usr/lib64/nvidia ./configure --enable-cpumining && make && sudo make install

That should get you to the point of having cgminer compiled for Nvidia on Fedora 18.  Feel free to post comments/corrections.