I found the same issue: Up2date flagged the .681 kernel as a new update, while it's been around a while. But a second run revealed that kernel 2.6.9-1.724_FC3 has just been released. It might be that not all the mirrors have it yet.
i tried to update the kernel that was just released i get a message " Your system is fully updated. No new packages are needed"
i guess cause the kernel is usually skipped but since this is the only package i need, why won't it let me install the update ?
Erik