debian sarge kernel question

[monky <jiangwei909@21cn.com>]

hello,everybody
i download debian sarge Disk 1 from internet and install it.
everything is successful.but i download other software in my computer.
when i compile there softwares,the system promt me "your must have
kernel header file".
i run 'uname -r' at my computer,i get some message "2.6.8-1-686".i
install debian sarge with linux26 and default settings.but sarge Disk 1
have not the kernel source code,so i use apt-get download a kernel
source ball and uncompress it in /usr/src.some question here,when i run
' apt-cache search kernel|grep 2.6.8|grep ^k|grep source',i get
following messages:
kernel-patch-2.6.8-hppa - Diffs to the kernel source for HP PA-RISC
(2.6)
kernel-patch-2.6.8-m68k - Diffs to the kernel source for m68k
kernel-patch-2.6.8-s390 - Diffs to the Linux kernel source 2.6.8 for IBM
S/390 and zSeries
kernel-source-2.6.8 - Linux kernel source for version 2.6.8 with Debian
patches
kernel-tree-2.6.8 - Linux kernel source tree for building Debian kernel
images

just you see,there have not about "2.6.8-1-686" recordes.
so i can not compile my application which require kernel header file
util i recompile my linux kernel with new kernel(kernel-source-2.6.8).
who can tell me why the debian sarge default install and the system
kernel is 2.6.8-1-686(or 386),but have not fit kernel source code???
because it, i must compile my kernel tow times (install and
recompile),i'am not understander why it???
sorry for my pool english:)