Get at least lilo 21.6. This was the first version to support ReiserFS. The alternative is to keep a small /boot partition that is ext2. The first option -- upgrading lilo -- is preferred. A better boot manager that we recommend for use is GRUB.

Install lilo after creating new lilo.conf entries for your new kernel and boot with it. The "root =" entry should point to the new root.

Reboot! You'll now have root on ReiserFS.

The above procedure was for putting root on ReiserFS, but it is pretty much what you will want to use when converting any of your partitions to ReiserFS. The procedure given in this article should work across distributions and partitions. But do let us know, in case you encounter any problems regarding the new kernel.