Kernel, install manually or through apt?

[Vegard|drageV <vegardlr@gmail.com>]

Hi everybody, 
I'm experimenting with the linux kernels, and have so far tried to
kernels available through apt-get, namely 2.4.27-1-386 (standard with
the installation in sarge) and 2.6.8-2-686 (running today).

Is there an easy to understand howto on manually installing a kernel
from kernel.org etc. for a newbie?

Are there more kernels available with apt, by adding lines to sources.list?

Besides that, if anyone have som hints or experinences to share with
me, I am all ears!

Thanks in advance, Vegard