To install:

mkdir -p /var/portage/overlays
cd $_
git clone [adress-of-overlay] ossdl

nano /etc/portage/make.conf || nano /etc/make.conf
PORTDIR_OVERLAY="/var/portage/overlays/ossdl"

By the next emerge --sync or eix-sync -u the new packages should be available for search.

You can find ready portage configuration files - (un)maskings, keywordings and package.use - online at http://git.ossdl.de/ . You will have to pick an appropriate branch, though.

For example, for latest AMD processors of the amdfam10 [1] family:

cd /etc
rm -r make.conf portage
git clone -b amdfam10 https://bitbucket.org/wmark/portage-configurations.git
ln -s portage/make.conf

Gentoo is not about compiling everything, don't waste your time on that. It is about customization. If you want to stick to the standards for 90% of all packages and if you are only interested about changing USE flags for the 10% where it matters - excellent. That is what the binhosts are for.

Find pre-compiled Gentoo packages for your architecture [1] here:

Obviously you will have to point Gentoo's Portage to these overlays. Modify your make.conf as follows:

FEATURES="parallel-fetch getbinpkg"
PORTAGE_BINHOST="http://binhost.ossdl.de/AMD64/Intel/CoreIx/x86_64-pc-linux-gnu/"

-- W-Mark Kubacki, 2012-08-01