Nick J. White's "njw" overlay has been added to the list of "registered" overlays (i.e. to layman-global.txt) recently. Besides other ebuilds it features an ebuild for the lastest version of GNU IceCat, the GNU project's zero- non-libre-bytes edition of Mozilla Firefox. Check it out through

# layman -a njw
# autounmask www-client/icecat-3.5.1
# emerge -av =www-client/icecat

I want Nick to become a Gentoo dev so please tell him if you like his ebuilds :-)