recompiling srpm's or tarballs means you won't get updates via yum.
here's how i recently got kernel 2.6.38-0.rc7.git2.3.fc16.x86_64 on f14 (not sure why it went straight to f16 not 15):
yum install fedora-release-rawhide.noarch
this will then enable /etc/yum.repos.d/fedora-rawhide.repo
name=Fedora - Rawhide - Developmental packages for the next Fedora release
note you must add the "includepkgs=kernel*" line to the bottom of that file to ONLY pull in kernels, otherwise you'll find you're upgraded to f15!
as i have an nvidia gfx card i also enabled the rpmfusion-nonfree-rawhide repo with "includepkgs=*nvidia*" to ONLY pull in nvidia rpms:
name=RPM Fusion for Fedora Rawhide - Nonfree
then a regular "yum update" will pull in the latest kernel and nvidia packages and keep them up-to-date when you use yum in future.