After upgrading to kernel 2.6.8.1 from 2.4 I used generate-modprobe.conf to make a modprobe.conf file out of modules.conf. But the former has modules which are used in kernel 2.4, but in 2.6 some of them have different names, some have been added, some removed. Do I have to correct modprobe.conf manually?

I may be wrong, but I think that, assuming you chose all the right options in the kernel configuration, you can just go into your kernel source directory and do (as root):

("make menuconfig" or "make gconfig" if you need to)
make
make modules
make modules_install
make bzImage
make install

This should put all your modules in the right places and configure them to load at boot. You'll probably still have some troubleshooting to do, but that's to be expected. You may need to copy /[kernelsourcedirectory]/arch/i386/boot/bzImage to /boot and make sure that LILO or GRUB is pointing to it. Don't forget to run "lilo" as root once you're done editing lilo.conf.

--Dane