Most likely... /usr/src/linux --that's where it is on my box
Do a google search for how to configure the kernel, there are tons of websites out there.
http://www.amigau.com/amigarealm/lin...re-kernel.html
http://www.linuxheadquarters.com/how...elconfig.shtml
Check these sites out especially the second link. I prefer make menuconfig.
In general what you'll do it...
1. cd /usr/src/linux
2. make mrproper
3. make menuconfig
4. make dep
5. make clean
6. make bzImage
7. make install
8. make modules_install
There is more but that's all i remember right now. Just google it and you'll find an answer out there