Sorry if the patch is giving people problems. I diffed in the kernel directory because the PKGBUILD (a.k.a. build script) for my Arch distro changes to that directory to compile the Nvidia module. It doesn't directly use the Nvidia installer.
For those using the Nvidia installer, here are step by step instructions, assuming both NVIDIA-Linux-x86_64-270.41.19.run (or whatever version you're using - sub in the right name if necessary in the instructions) and kernel-3.0-rc1.patch.txt are in your home directory, and that you use sudo to run the Nvidia installer:
$ sh .NVIDIA-Linux-x86_64-270.41.19.run --extract-only
$ cd NVIDIA-Linux-x86_64-270.41.19.run/kernel
$ cat ../../kernel-3.0-rc1.patch.txt | patch -p0
$ cd ..
$ sudo ./nvidia-installer