Where is kernel 2.6 source to compile Nvidia drivers?

Hi!
I downloaded a kernel 2.6 source for my installed knoppix3.6 and when run nvidia driver it can´t compile kernel because not match with installed kernel.
Which kernel i must download and when it is?

This one?: http://developer.linuxtag.org/knoppi...Custom_all.deb

You could also get a source from kernel.org, compile it and run it instead:
http://newbiedoc.sourceforge.net/tut...el-pkg.html.en
http://www.osnews.com/story.php?news_id=2949&page=4