Time to CHOOSE INSTALL CONFIGURE COMPILE the LINUX KERNEL source in gentoo
 

Ha ha, yes! Time to step 7 (from the manual) in my Gentoo installation: Configure the Kernel.
All the search engines turn up multiple hits with lots of articles, ok, suggestions? Best online articles, personal experiences, advice for doing this for the first time?

This would probably be a good place to start: http://kernel-seeds.org. Make sure you don't forget any of the steps mentioned in the handbook as well. If you get stuck with kernel panics, try grabbing the latest slackware-current generic .config file, copy it into your /usr/src/linux directory, update it for the latest kernel (they're usually a few versions behind) with make oldconfig, switch the processor options to use the CPU you actually own, and compile in the drivers you need specifically (so I don't need a RAMDISK).

A good tool for finding which modules you need is here: http://kmuto.jp/debian/hcl/. Load up a good live distro, paste the output into the web page, and it should tell you most of the kernel modules you need. Also, you probably don't want to inline wireless networking modules or alsa modules: just leave them as modules.

Hope this helps!