Short : Just extract to root file system and edit bootloader config.

Long :

Step 1 :
 Fetch :
  Option 1 :  Fetch only image and modules (good for just trying out):
    $ wget http://hirakendu.mooo.com/helium-sources/kernel-2.6.22-h9-r6-precompiled.tar.bz2
  Option 2 : Fetch full sources (better for installing external drivers) :
    $ wget http://hirakendu.mooo.com/helium-sources/kernel-2.6.22-h9-r6-precompiled-full.tar.bz2

Step 2:
 Extract : 
    $ tar  -xjpf  kernel-2.6.22-h9-r6-precompiled*.tar.bz2  -C  /
  (Add verbose option -v if you want. The full sources may take some time
   to extract. It also occupies about 500 MB of disk space.)
  If using full sources, may also link it with /usr/src/linux :
    $ mv /usr/src/linux /usr/src/linux-old
    $ ln -s /usr/src/linux-2.6.22-helium9 /usr/src/linux

Step 3 :
  Add bootloader entries (example : grub, root=/dev/sda5, swap = /dev/sda6) :

    title Helium Sources
    root (hd0,4)
    kernel (hd0,4)/boot/vmlinuz-2.6.22-helium9 root=/dev/sda5 vga=791 resume=swap:/dev/sda6 libata.atapi_enabled=1 noirqbalance quiet

Last rites (optional) :
  Review through /etc/modprobe.d/blacklist and  /etc/modules.autoload.d/kernel-2.6.
  Preferable add the line 'ladder' or 'menu' in /etc/modules.autoload.d/kernel-2.6
  to autoload a cpuidle governor module (for using higher C-states and power saving.)
  And also, run :
    $ update-modules


Thats it ;-). Good luck with reboot :p !


Note : Created as follows -
   $ cd /
   $ time tar -cjps --atime-preserve -f /root/kernel-2.6.22-h9-r6-precompiled-full.tar.bz2  boot/vmlinuz-2.6.22-helium9 boot/System.map-2.6.22-helium9 boot/config-2.6.22-helium9 lib/modules/2.6.22-helium9/ usr/src/linux-2.6.22-helium9/ usr/src/linux

Hirakendu Das
(20070827)