theres a site which has the source files for every linux kernel at
www.kernel.org serch for a PPC kernel source there i recommend ver. 2.4.18 or 2.4.19 its been out for a while and can be considered stable, if you choose a different version avoid those with odd numbers ie. 2.3.xx or 2.5.xx as these are development versions and are not stable trees. Once you have downloaded the source uzip it to a directory you need to be root to do the following commands so anywhere will do /usr/share/ is probably best. open a terminal or shell and cd to the directory of the unpacked kernel and type..
make xconfig
a prompt will apear where you can select options for the kernel it is usally intelligent and will select options suited for your system. once done click on the save config and close button which will return you to the console there you need to run the following commands in this order
make dep
make clean
make bzImage
then after that if you have used any modules you will need to run the relavant commands for them. However i dont know these so goto the LDP at
www.tlpd.org and read the KERNELHOWTO this will describe the whole kernel update and install routene including how to configure your loader (LILO, GRUB ect). hope this helps :-D
