Nice howto. Thank you for time and effort in helping us!

At least with CentOS 5.x, you can ditch all of the mkinitrd and grub.conf manual changes by just running something like:

/sbin/new-kernel-pkg --package kernel --mkinitrd --depmod --install 2.6.25.7

as root to do all of that for you.

Also, you can now run "make rpm" for the kernel to create a well behaved kernel.rpm (minus the "new-kernel-pkg" from above).