I updated from 2.6.13-15.7-default to 2.6.15-rc6-git2-20051223230007-default by downloading the kernel-default RPM from
ftp://ftp4.gwdg.de/pub/linux/suse/ap...el-of-the-day/
. If you use the 64 bit version of SUSE then you'll need to use those ones, and you will need to update all kernel versions you're using (default, nonGPL, debug etc.) at once to avoid dependency issues.
Kernel upgrades can go wrong so backup your files before upgrading.