You won't find better information than the APT-howto on the Debian site!
Kernels are one thing that people generally do compile from source. Read the kernel howto to get the gist of what this entails.
If you do want to get a stock kernel,
apt-get update
apt-cache search 2.6.2
That will give you a list of files relating to the kernel. apt-get install the image package for your architecture to install the new kernel.
As for KDE 3.2, even debian unstable doesn't have that yet. go to kde.org and browse for their backports.
Learn to love apt!
--Rounan