best place for information is the kernel howto at tldp.org
basically if you have a fully working 2.4.18 then i'd recommend that you use the existing config file (possibly at /boot/config-2.4.18 if you instaled that one from an rpm) when you run "make xconfig" or "make menuconfig" for the new kernel. This will load 99.9% of the current settings and you can then trim away what you don't want, CAREFULLY. after that, just follow the instructions as oer howto. you shouldn't need to do anything as far as individual devices are concerned, just make sure lilo or grub is updated properly.and NEVER delete the old kernel and settings until you are stupidly confident that the new one works. always duplicate, don't replace!