I want to install my wlan card for ubuntu what i already successful did in mandrake. So I have an Internet connection in mandrake and need to install the kernel-sources for ubuntu with kernel 2.6.12-8-686. Now I am not sure which source to choose from kernel.org because they seem to have different naming systems. Unfortunately I cant make an apt-get because there is only the wlan...

Thanks for help

No different systems on kernel.org! Download the latest - linux-2.6.14.
Others:
2.6.14-git4 - newer but less stable, it is created automatically based upon
the 2.6.14.
2.4 kernels are of a great stability but only valuable for the considerable
servers. Not all programs can work properly under old kernels. But migrating
from 2.4 to 2.6 is alittle complex and almost impossible on a big servers, so
this thread is also supported. Also I can repeat it is of a great stabillity.
The same story with 2.2 and 2.0 kernels. It is a bad idea to download one of
these kernels for desktop. Choose 2.6 for now.
Also there people who develop kernel. You can test there work using -ac or -mm
kernel versions. In common it is useful for people interested in kernel
developing E.g. Linus can investigate these kernels and change the main
thread appropriate if he like.

Hope you understood what I said regardless to my English and it helps.

And the best sollution is to choose the latest stable linux-2.6.14.

ok, i managed to get to a place where i don't need the wlan-card to connect ubuntu to the internet, but have a connection through the network-card. but when i make a "apt-get install kernel-source-'uname -r' ", it tells me there isn't such a kernel-source (2.6.12-8) and in the application installer I really only see the 2.6.10 and 2.6.11 kernel source - can i just take the 2.6.12 from kernel.org and unpack it in /usr/src ?

thanks

Of course, you could download a tarball from kernel.org and extract it
anywhere you want, though the common used destination really is /usr/src. No
need to wait repository for the lates kernel (at least I do not see it). The
only thing you should is to remove kernel-src and kernel-doc (indeed I do not
know how are they named exactly, but something like these), for tarball already
contains them. And also you will not have these packages (and it is good), you
do not need them. Advantages: when new kernel releases you can easily apply the
appropriate patch from kernel.org and do not download kernel entirely. It is
not true for the source from repositories. Disatvantage: you cannot build a
Debian package from source. If you want aptitude show it you should not use
source from kernel.org. If you do, you will have a kernel but no package. It is
alittle ambigous but I had never any problems with it.

But even though I can't build a debian package I can build a module for the wlan-card? and do I have to take care with the ubuntu update procedure later?

Of course you can build any module. If you never compiled a kernel, it is
better to follow instructions from README strictly. Also you can find alot
information on any linux forum, including LQ.
After you compile kernel, forget to update it from repositories. Look for a new
version on kernel.org, also the latest kernel you could see on the LQ homepage.

Type at the cli, apt-cache search kernel-images to see which binary kernels are included. Than you can do apt-get install kernel-image-2.6.whatever.