Hi. I'm using Fedora Core 3 and I wonder if it's really necessary to update the kernel, if it is, is it safe to update it with yum?? I mean, after updating the kernel with yum will I have to go through the kernel configuration or recompilation?? (something I don't know how to do). Also, after updating the kernel will I have to reinstall my graphic card and modem drivers??
Thanks in advance.

Well, if the new kernel provides a performance enhancement, particular fix, driver/hardware support that you want, you may want to update it. Otherwise not necessary. But yes, if you want to learn something new, understand how linux works, or even for satisfaction, you may do it anyway.
FC3 comes stocked with 2.6.9, so its relative easy to compile and install the latest kernel without making a lot of changes to the system to adapt the new kernel.
You may have to re-install, re-compile your modem and video card driver after the update. Especially, nvidia driver, alsa drivers they have to be recompiled after every kernel update. Incase of alsa, you can compile it with the kernel, the ones that included with it.

I'll first do some research on compiling the kernel, since I tried it once on SuSE, and it was too complicated for me (lot's of questions I didn't know how to answer). Does anyone know an ease guide on kernel compilation? Thanks in advance.

You are welcome to try my guide, feel free to give me any feedback. If you wait a few days I will have it updated for kernel 2.6.11.5 and the latest nvidia drivers. However it should still give you a good start:

http://www.mjmwired.net/resources/mjm-kernel-fc3.shtml

Also, MY OPINION: I do not recommend upgrading kernels very frequently. Once you find everything works perfectly, then you should always verify what new enhancements were made in a newer kernel and then see if it is worth your time. Very frequently what happens is some change in a kernel will affect certain people's hardware and may "break" some functionality. ... Yes every additional driver you installed will need to be re-installed. Which opens the door to other potential conflicts where some drivers may not work with the newest kernels.

Necessity should always be determined on 2 major parts: 1 security, 2 support. If there is some serious security issue that you know affects you, upgrade. If there is some serious hardware support you know you need, upgrade.

Well, if there's a risk of having conflicts when reinstalling the nvidia and modem drivers, I think it 'd better not to upgrade in my case, unless the default FC3 kernel has some security issue. Thanks for the advice and the link.

odise077,
I wasn't trying to discourage you. Yes, you have to re-install/re-compile the alsa and nvidia drivers but thats not hard and there will be no conflict. Remove your current nvidia driver and download the latest and install it after the kernel upgrade. As for alsa, it comes builtin with the kernel, you can use that easily. For your modem drivers, check the vendors update and find out if ir works with the new kernel or not.

just check if you can get nvidia kernel module appropriate for the new kernel before you use it that's all

OK, I'll give it a try to see what happens