Here's the hyperlink to the upgrade.
Just follow all of his instructions, including the appended ones, and you won't have problems with the kernel. I did everything at once, including making the necessary changes for my USB devices and I was able to use my USB keyboard and mouse when I rebooted into 2.6.3.
I don't have sound now, but I believe that's because you need to install ALSA sound drivers with 2.6.x
I'm not for sure if you need the source rpms. Could someone confirm or unconfirm this?