The kernel acts as a mediator between your programs and your ["Hardware"]. First, it does (or arranges for) the memory management for all of the running programs (processes), and makes sure that they all get a fair (or unfair, if you please) share of the processor's cycles. In addition, it provides a nice, fairly portable interface for programs to talk to your hardware. There is certainly more to the kernel's operation than this, but these basic functions are the most important to know.
An odd number (2.1.13, 2.3.2 ...) is a unstable kernel. An even number is a stable kernel and ready for ["compilation"] e.g. (2.0.36, 2.2.17, 2.4.9 ...).
The last kernel version number appears at http://www.kernel.org and you can see your kernel version typing
in a ["terminal"].
The kernel is generally in the ["?BootDirectory"] (/boot).
Latest: ["Kernel2dot6"] (2.6). See http://www.kernel.org/
DebianKernel - the Debian Kernel Team's page
- ["KernelALaDebian"] about how to install and update your kernel creating a .deb file.
[http://svn.debian.org/wsvn/kernel/dists/trunk/linux-2.6/debian/patches/?rev=0&sc=0 Patches included in the Debian Linux kernel]
http://www.debian.org/releases/stable/i386/ch-post-install.en.html Compiling a new kernel.
[http://home.triad.rr.com/owdawg/articles/kernel.html Compiling/Recompiling your Kernel in 9 simple steps].
http://www.treblig.org/Linux_kernel_source_finder.html Kernel finder.
http://www.linuxgazette.com/issue32/bandel.html Linux Kernel Installation
http://lists.debian.org/debian-kernel/ Debian Kernel List.
http://www.wikipedia.org/wiki/Linux_Kernel Wikipedia article about Kernel].