These ebuilds come from http://overlays.gentoo.org.
If you have some problems, go to the official site first.
madwifi-ng : Next Generation driver for Atheros based IEEE 802.11a/b/g wireless LAN cards ( http://www.madwifi-project.org/ )
madwifi-ng-tools : Next Generation tools for configuration of Atheros based IEEE 802.11a/b/g wireless LAN cards ( http://www.madwifi-project.org/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a wschlich-testing
For Paludis use this rsync : rsync://gentoo.zugaina.org/wschlich-testing-portage
If you have a problem : ycarus(-at-)zugaina.org