Something

fstab
====================================================================================
/dev/hda1        /boot   ext2    defaults                1 2
/dev/hda2        none            swap            sw              0 0
/dev/hda3        /       ext3    defaults                0 1
none        /proc     proc    defaults          0 0
none        /dev/shm  tmpfs   defaults          0 0


grub.conf
====================================================================================
#Default to non-genkernel
default 1

#if that fails, let's fall back to genkernel
fallback 0
timeout 10
splashimage=(hd0,0)/grub/splash.xpm.gz

#LiveCD GenKernel
title=Gentoo Linux
root (hd0,0)
kernel /kernel-genkernel-x86-2.6.17-gentoo-r7 root=/dev/ram0 init=/linuxrc ramdisk=8192 real_root=/dev/hda3
initrd /initramfs-genkernel-x86-2.6.17-gentoo-r7

#custom kernel
title=Gentoo-NeT
root (hd0,0)
kernel /boot/vmlinuz root=/dev/hda3



produces:
VFS: cannot open root device "hda3" or unknown-block (0,0)
please append a correct root= boot option
kernel panic - not syncing VFS unable to mount root

when trying to boot the custom kernel. The genkernel listing above works just fine...