I have build my Linux kernel (3.0.1) for my raspberry pi with those following steps.

1. Downloading kernel source
2. tar xvf source.tar.bz2
3. downloading arm cross compilation tool.
4. tar xvf arm-2010q1-202-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2
5. setting up path for cross tool export PATH=$PATH:/home/shan/<cross tool folder>/bin/
6. after entering linux source dir make ARCH=arm versatile_defconfig (is this reliable   with raspberry pi)
7. make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi-
8. zImage is generated in /arch/arm/boot

My question is how could I build kernel.img. I think it contains zImage + ramdisk but how could i build this? Can anyone guide me to making ramdisk and pack these two into kernel.img file? I want to boot this kernel in raspberry pi.