Step # 1 Get Latest Linux kernel code
 Visit http://kernel.org/ and download the latest source code. File name would be linux-x.y.z.tar.bz2, where x.y.z is actual version number. For example file inux-2.6.25.tar.bz2 represents 2.6.25 kernel version. Use wget command to download kernel source code:
 $ cd /tmp
 $ wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-x.y.z.tar.bz2
 Note: Replace x.y.z with actual version number.

Step # 2 Extract tar (.tar.bz3) file
 Type the following command:
 # tar -xjvf linux-2.6.25.tar.bz2 -C /usr/src
 # cd /usr/src

 Step # 3 Configure kernel
 Before you configure kernel make sure you have development tools (gcc compilers and related tools) are installed on your system. If gcc compiler and tools are not installed then use apt-get command under Debian Linux to install development tools.
 # apt-get install gcc
 Now you can start kernel configuration by typing any one of the command:
       
 $ make menuconfig - Text based color menus, radiolists & dialogs. This option also useful on remote server if you wanna compile kernel remotely.
 $ make xconfig - X windows (Qt) based configuration tool, works best under KDE desktop
 $ make gconfig - X windows (Gtk) based configuration tool, works best under Gnome Dekstop.
 For example make menuconfig command launches following screen:
 $ make menuconfig
 You have to select different options as per your need. Each configuration option has HELP button associated with it so select help button to get help.

Step # 4 Compile kernel
 Start compiling to create a compressed kernel image, enter:
 $ make
 Start compiling to kernel modules:
 $ make modules
 Install kernel modules (become a root user, use su command):
 $ su -
 # make modules_install

Step # 5 Install kernel
 So far we have compiled kernel and installed kernel modules. It is time to install kernel itself.
 # make install
 It will install three files into /boot directory as well as modification to your kernel grub configuration file:

 System.map-2.6.25
 config-2.6.25
 vmlinuz-2.6.25

 Step # 6: Create an initrd image
 Type the following command at a shell prompt:
 # cd /boot
 # mkinitrd -o initrd.img-2.6.25 2.6.25
 initrd images contains device driver which needed to load rest of the operating system later on. Not all computer requires initrd, but it is safe to create one.

Step # 7 Modify Grub configuration file - /boot/grub/menu.lst
 Open file using vi:
 # vi /boot/grub/menu.lst
 title           Debian GNU/Linux, kernel 2.6.25 Default
 root            (hd0,0)
 kernel          /boot/vmlinuz root=/dev/hdb1 ro
 initrd          /boot/initrd.img-2.6.25
 savedefault
 bootRemember to setup correct root=/dev/hdXX device. Save and close the file. If you think editing and writing all lines by hand is too much for you, try out update-grub command to update the lines for each kernel in /boot/grub/menu.lst file. Just type the command:
 # update-grub
 Neat. Huh?
 
Step # 8 : Reboot computer and boot into your new kernel
 Just issue reboot command:
 # reboot