When you update via yum/synaptic and a new kernel is installed, the old one is not removed. This is deliberate. It is possible that the new kernel doesn't have a driver needed by your system or you may have compiled software specifically for the old kernel. You can install more kernels if you'd like. You can choose which one is loaded into memory at boot time. The default is set in the file /boot/grub/grub.conf .
So, there's no problem having two on your system. If everything's been working fine for a while you can safely remove the older one.
I'm guessing the two you have are called :
The second one (with the lower version number) is the older one.
Oh, well it just was weird to me and I did not know if it was going to be an issue